Download Wrath Thor UNSIN

Health Sciences 1I06
The UNSIN Report
Thursday, April 5, 2012
Group Name: TEAM THOR
Group Members:
Alexandra Annibale
Clarence Chan
Bonnie Cheung
Amanda (Vincci) Chiu
Victoria Maich
Amita Mall
Laila Nasser
Navneet Natt
Jessie Peng
Catherine Yang
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
SECTION 1: At a Glance (Abstract)
Sin Explored: Wrath
Stimuli perceived as threatening can naturally result in the manifestation of aggressive
behaviour. In some cases, however, one may inappropriately perceive a stimulus as
threatening, and in turn, respond impulsively and irrationally. This state of extreme
volatility has many names, the most notable being reactive aggression, or wrath.
Specific Molecular Target:
When analysed from a molecular perspective, it has been found that aggressive
behaviour is especially demonstrated upon hyperactivity of the amygdala (the emotionprocessing neural centre), coupled with hypoactivity of the orbitofrontal cortex (OFC;
the decision-making neural centre). Furthermore, research has demonstrated that the
neurotransmitter serotonin is the primary neurotransmitter responsible for allowing the
OFC to have an inhibitory effect on the amygdala.
Proposed Intervention:
Lokitonin© is a bidentate ligand molecule acting specifically on serotonin (5-HT)
receptors: it is a full agonist to 5-HT1A postsynaptic receptors and antagonist to the 5HT2A receptor in the OFC. The component acting as a 5-HT1a agonist mimics serotonin
in the OFC, allowing for inhibitory signals to be sent to the amygdala. However, due to
the ubiquity of these receptors in the brain, the antagonistic component of the drug
ensures that the drug will travel to the intended locus of intervention, as 5-HT2A
receptors densely populate the OFC, and are sparse in other neural regions.
-2-
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
SECTION 2: Framing the Problem
Some forms of aggression are evolutionarily necessary to transcend natural
selection and assure self-preservation. The type of aggression that best describes the
notion of wrathful behaviour is reactive aggression. Reactive aggression is the product
of an exaggerated threat perception, coupled with the inability to subdue this
heightened emotional state.1 This failure to rationalize external circumstances has the
potential to be detrimental to not only oneself, but also to those surrounding.
Accordingly, understanding the underlying mechanisms of reactive aggression allow for
the development of methods that mitigate its potentially devastating consequences.
Definition of Wrath:
Wrath is a disproportionate response to a provocative stimulus, resulting in a
violent burst of aggression, characterized by impulsivity and irrationality. Wrath is
identified by excessive reactivity in the amygdala due to the failure of the orbitofrontal
cortex (OFC) to effectively inhibit affective signals sent from the amygdala. Thus, the
affective limbic signals are channeled into physical or verbal violent behaviours.2
Our Proposed Pathway
The amygdala is the part of the limbic system that processes emotional reactions.
In healthy individuals, the amygdala receives affective stimuli and sends them to the
OFC where emotional signals are regulated through top-down modulation. However, in
aggressive individuals, the OFC is unable to suppress the affective stimuli, causing the
individual to display symptoms of wrath. In other words, the inability of the OFC to
inhibit aggressive stimuli causes the amygdala to send amplified signals to the anterior
hippocampus (AHA), the bed nucleus of stria terminalis (BNST), and finally, to the
periaqueductal gray (PAG). The efferent projections from the PAG extend to structures
that mediate somatomotor and autonomic mechanisms of impulsive aggression.3
Aggressive behavior can thus be accounted for by the pathway illustrated in figure 1 of
the appendix.4
Locus of Intervention: The Orbitofrontal Cortex
As the amygdala mediates all affective processes, targeting it would increase the
risk of disrupting one’s ability to regulate emotional response to stimuli. Therefore, the
OFC is a more ideal locus for intervention to attenuate aggression. We proceeded in our
investigation by exploring the major biochemicals involved.
Testosterone
The steroid hormone testosterone regulates serotonin levels through androgen
and estrogen receptors in the OFC. However, the exact mechanism by which it does so
remains unclear.5 Furthermore, testosterone’s dual nature as both a neurotransmitter
and a hormone will result in adverse effects if it is interfered. Therefore, testosterone
could not be justified as a target molecule.
-3-
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
Gamma-aminobutyric acid (GABA)
The correlation between low GABA levels in various brain regions and heightened
aggression has been widely observed.6 Animal experiments have revealed GABA
receptors are highly localized primarily in the striatum and olfactory areas of the brain,
neither of which are involved directly in aggression.6 Although there is a dense
collection of GABAergic neurons concentrated in the amygdala, we refrained from
targeting this locus since it is the emotion-processing center in the wrath pathway.
Furthermore, preclinical dose-response trials have shown variation amongst individuals
in aggressive response to drugs that enhance the natural effects of GABA by allosteric
modulation.2 The uncertainty surrounding GABA’s function in aggression modulation
made it a weak candidate for our drug.6
Dopamine
Dopamine is involved in motivated behaviour and reward processing, and
hyperactive dopaminergic signaling has been linked to impulsive aggression.4 Elevated
dopamine levels have also been observed in individuals just before, during, and after
intense conflicts.7 Animal models have shown that serotonin depletion coupled with the
addition of dopamine can trigger impulsive aggression.7 However, dopamine’s role is
secondary to that of serotonin in modulating the aggression pathway. Dopamine’s
indirect role discouraged us from making it a target molecule in the development of the
drug and pushed us to look further into serotonin.
Serotonin
Extensive research supports that serotonin has a major influence on modulating
impulsive aggression.2 The Serotonin Deficiency Hypothesis states that insufficient
levels of serotonin in the prefrontal cortical regions have consistently been reported in
individuals who display impulsive aggression.8
The OFC uses serotonin as a fuel to suppress the affective signals from the
amygdala through a reciprocal neural pathway. When there is a lack of serotonin in the
OFC, it is hypoactive and unable to adequately suppress the affective stimuli coming
from the amygdala.2 It is the dorsal raphe nucleus (DRN) that provides serotonin to all
regions of the brain, including the OFC.9
The DRN was considered as a potential locus of intervention, however, targeting
the DRN presented several challenges. The main function of the DRN is to project
serotonin to the rest of the brain. It contains the highest concentration of serotonin
receptors in the brain – especially 5-HT1A autoreceptors.10 Although stimulation of
these receptors in the DRN would increase serotonergic neurotransmission in the OFC,
it would do so at the consequence of increasing serotonin in numerous other brain
regions, thus increasing the risk of side effects.10 For example, serotonin in the DR
heavily regulates REM sleep; upsetting the sleep cycle of an already wrathful subject has
the potential for causing further irritability.9 It was thus deemed appropriate to directly
target the OFC and restore serotonergic signaling in this brain region specifically.
Serotonin’s modulation of impulsive aggression in the OFC occurs via binding to
5-HT1A, 5-HT2A, and 5-HT1B receptors. The advantages and disadvantages of targeting
each of these receptors were evaluated individually.
-4-
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
5-HT1B
5-HT1B receptors can be found both pre- and post-synaptically in various areas
of the brain outside of the OFC, including the basal ganglia and the striatum.4 By
administering a 5-HT1B agonist as treatment for wrath, it is likely that many adverse
side effects would occur as a result of dispersed ligand binding throughout the brain.
Furthermore, literature indicates that 5-HT1B receptors can elicit contrasting
behavioural effects depending on their location. For example, in the prefrontal cortex,
they function as terminal receptors that inhibit the release of dopamine, however, in the
striatum or the basal ganglia, they act as autoreceptors to inhibit the release of
serotonin.11 5-HT1B receptors also play a secondary role in the release of other
neurotransmitters such as acetylcholine, glutamate, dopamine, norepinephrine and
GABA which can produce multiple physiological effects aside from aggression.11 Some
studies suggest that 5-HT1B receptors may reduce impulsivity, but not aggression.4
After careful consideration of each of these factors, it was concluded that the 5-HT1B
receptor was not an ideal candidate.
5-HT1A and 5-HT2A
5-HT1A and 5-HT2A have both demonstrated important and consistent roles in
the modulation of impulsive aggression, specifically within the OFC. Multiple research
studies have shown that antagonizing 5-HT2A receptors and agonizing 5-HT1A
receptors attenuate impulsive aggression.4 The distinguished role of the 5-HT2A and 5HT1A postsynaptic receptors in the modulation of aggression makes them promising
targets. Moreover, the fact that 5-HT2A receptors are found most densely in the OFC,12
and are frequently colocalized with 5-HT1A receptors in this region,13 enables the design
of a heterodimeric drug with high selectivity for both receptors.
Justifying the OFC as an ideal locus of intervention with Intermittent
Explosive Disorder (IED)
IED is an impulsive control disorder characterized by random episodes of
destruction or assault due to the failure to inhibit aggressive impulses. The level of
aggression displayed during an episode is greatly disproportionate to the stimulus that
triggered it.14
The mechanism behind IED is a useful tool to study the neurobiology of
impulsive aggression in humans.14 Moreover, since IED’s criteria matches that of a
wrathful individual, the mechanism behind IED serves as an excellent tool to
hypothesize ways to alter neurotransmitter signaling to suppress impulsive aggression.
Research has been done on patients with IED to identify two characteristics of impulsive
aggression: (1) Low levels of presynaptic cortico-limbic 5-HT causes a predisposition to
impulsive aggression and (2) Individuals with this predisposition trait have increased
binding to 5-HT2A receptors in the OFC, a state condition associated with impulsive
aggression.14 Thus, the mechanism behind IED demonstrates that antagonizing 5-HT2A
receptors in the OFC, as well as mimicking serotonergic neurotransmission via 5-HT1A
agonists are ideal mechanisms to attenuate aggression.
-5-
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
SECTION 3: Accomplishments, Future Plans & JYP (5 pages MAX)
Features of Lokitonin
Postsynaptic serotonin receptors 5-HT1A and 5-HT2A are highly co-expressed in
the prefrontal cortex (PFC) and both are implicated in aggressive behaviour.3 Lokitonin
is a heterodimer that targets both receptors simultaneously, consisting of a 5-HT2A
antagonist and a 5-HT1A postsynaptic receptor agonist. The 5-HT2A antagonist displays
high affinity and high selectivity for the target receptor. This ensures that the drug
travels primarily to the OFC – the brain region most dense in 5-HT2A receptors and
thus hinders Lokitonin from binding to other receptors irrelevant in this context.12 By
acting specifically in the OFC, Lokitonin produces a localized response and minimizes
side effects.
The highly-selective 5-HT1A agonist of Lokitonin preferentially binds to the
orthosteric site of the 5-HT1A postsynaptic receptor in the OFC.15,16 The assumption that
Lokitonin will simultaneously bind to these two receptors is based on probabilistic
grounds and there may be variable binding as illustrated in Figure 2 found in the
appendix. Regardless, either mode of binding will have an anti-aggressive effect due to
the equal involvement of the two receptors in aggression.s4,13
Administration
Lokitonin is designed to prevent the onset of obscene displays of aggression by
accounting for the serotonergic imbalance in the OFC. Oral administration is the most
effective method of delivering Lokitonin as opposed to immediate-release delivery
systems such as nasal sprays and intravenous injections.17 Daily and long-term
administration of Lokitonin is adopted because stimulus-induced wrath attacks tend to
be unpredictable. Consequently, treatment of the symptoms at every occurrence would
be unfeasible.
Drug Delivery System
In order to optimize the delivery of Lokitonin to the brain through the systemic
pathway, Lokitonin has been encapsulated in functionalized carbon nanotubes and
coated in an additional hydrophilic matrix.
The hydrophilic matrix allows for sustained and zero-order release of Lokitonin
in the body, ensuring non-diminishing and long-lasting effects for up to 24 hours.17,18
The release mechanism for Lokitonin has been confirmed through a variety of in vitro
pharmacokinetic tests. Pharmacokinetic testing was also used to verify that the capsule
followed the criteria set out by Lipinski’s Rule of Five in order for it to pass the bloodbrain barrier (BBB).19
Upon absorption into the bloodstream, Lokitonin travels to the brain enclosed in
highly specific and customized carbon nanotubes. These nanotubes protect Lokitonin
from enzymatic degradation in the blood and deliver the drug to the brain in high
therapeutic concentrations. The nanotubes are combined with functional groups that
interact with the BBB allowing Lokitonin to pass the barrier and target the OFC.20 The
effectiveness of BBB penetration was tested using in vivo fluorescent imaging
techniques.20 Toxicological tests were also conducted to ensure that the nanoparticle
-6-
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
formulation did not produce toxic side-effects.
In vitro testing
SPR Technology
Since the initial development of Lokitonin, this drug has undergone intensive
testing to ensure its safety for the target population. One of our earliest tests measured
the binding affinity of Lokitonin to 5-HT1A and 5-HT2A receptors using SPR
technology. SPR allows the real-time, label-free quantification of molecular binding
kinetics and affinities.21 This was used to ensure that Lokitonin interacted with 5-HT2A
receptors with high affinity in order for Lokitonin to act specifically in the OFC. After
performing the direct detection method, Lokitonin demonstrated a high affinity to 5HT2A receptors with a calculated equilibrium constant (KA) in the range of 105 – 1012
LŸmol-1 .22 Lokitonin showed a relatively lower affinity for the 5-HT1A receptor
compared to the 5-HT2A receptor.
FRET analysis
Next, we measured Lokitonin’s efficacy as a potential drug. This was done on cell
lines containing serotonin receptors, which determined Lokitonin’s biochemical
response in the signal transduction mechanism of the wrath pathway. The 5-HT2A
receptor is a G-protein coupled receptor (GPCR), belonging to the phosphoinositide
secondary messenger system.23 We expected Lokitonin to reduce the production of
inositol 1,4,5-triphosphate (IP3), a secondary messenger molecule.24 We performed
FRET analysis on 5-HT2A receptor cell lines to measure intracellular IP3 levels at
various concentrations of Lokitonin.25 We compared the results to a negative and
positive control test, which used, a 5-HT2A agonist (251-NBOMe) and a 5-HT2A
antagonist (nefazodone), respectively.24,26 We plotted a dose-response curve (Figure 3 in
the appendix) and were able to deduce that Lokitonin exhibited high efficacy and
potency as a 5-HT2A antagonist.
FRET analysis was also performed on a 5-HT1A receptor cell line.27 Activation of
the 5-HT1A GPCR leads to the production of the secondary messenger molecule cyclic
adenosine monophosphate (cAMP); therefore we expected Lokitonin to increase cAMP
production. A 5-HT1A agonist (F 11440) was used in the positive control test, while a 5HT1A antagonist (WAY-100635) was used in the negative control test.28,29 From the
dose-response curve (Figure 4 in the appendix), it was inferred that Lokitonin also
displayed high potency and high efficacy for the 5-HT1A.
Autoradiography
In order to test Lokitonin’s ability to pass the BBB and selectively to 5-HT1A and
5-HT2A receptors in the OFC in vivo, an autoradiographic scan of post-mortem brains
was conducted using a radiotracer on the drug.30 Figure 5 in the appendix depicts
experimental scans that show Lokitonin preferential binding to 5-HT1A and 5-HT2A
receptors in the OFC.
In Vivo Animal Testing
Prior to conducting clinical testing, multiple animal tests were performed to
-7-
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
construct a drug safety profile. One such test used isolation and resident-intruder
paradigms to study the effects of Lokitonin on aggressive mice.31,32 Adult male mice
were used to serve both as the experimental mice and the stimulus intruder mice. The
former were aggressive and experienced fighters, while the latter were nonaggressive.33
Impulsive aggression was induced in the experimental mice by placing an intruder
mouse into their home cage.34 It was expected that Lokitonin would reduce impulsive
aggression in these experimental mice.
Observational tests
The aggressive mice were kept isolated for 21 days, to induce aggressive
behaviour.35 After the isolation period, the mice were trained to attack an intruder
mouse upon entering their home cage. Attacks were measured via the number of bites or
flank marks on the intruder mice. Attack latencies were recorded for each mouse. Mice
with attack latencies of less than 10 seconds were representative of impulsive aggression
and thus were used for further study.36
The impulsively aggressive mice were once again exposed to an intruder mouse
and their number of attacks was recorded before and after drug treatment, for a
duration of 10 minutes each. The drug treatment consisted of a microinjection with
either a concentrated solution of Lokitonin (2 mg) or a control saline solution of 20%
dimethyl sulfoxide into the OFC.33
Results
Upon the microinjection of Lokitonin, the mice displayed decreased aggressive
behaviour relative to that of the control group.35 See Figure 6 in the appendix for a
graph regarding the number of bites and flank marks made by the aggressive
experimental mice on the intruder mice, pretreated either with saline solution or
Lokitonin.
Side Effects and Toxicity
The toxicity of Lokitonin was tested by performing daily microinjections of
Lokitonin (2 mg) into the OFC of the aggressive mice for a duration of 90 days. The
carcinogenicity and long-term side effects of the drug were determined a longer period
of experimentation in the range of 5-6 months.37
The lethal dose (LD50) was determined by orally administering Lokitonin in
increasing amounts. From the mouse lethal dose, the human lethal dose was
calculated.38 This value was subsequently used to determine the maximum appropriate
dosage of Lokitonin for the human clinical trials.
Human Clinical Trials
Lokitonin was meticulously monitored in the first two phases of human clinical
trials before finally entering phase three to determine its effects in IED patients.37 We
were careful to use only those therapeutic doses of Lokitonin which had been
established as safe and efficacious in preclinical and phase 1 clinical testing.
-8-
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
Background
We wanted to determine whether Lokitonin would produce a favourable
treatment response as compared to a placebo response for impulsive aggression in IED
patients. Since low serotonin levels in cortical brain regions cause IED patients to
display wrathful behaviour,39 administering Lokitonin to patients diagnosed with IED
would consequently reduce impulsive aggressive behaviour.
Research Diagnostic Criteria
In this controlled study, we selected patients that scored greater than or equal to
15 on the Overt Aggression Scale-Modified (OAS-M) and who had fulfilled Axis I
impulse control disorder, DSM-IV criteria for IED.40 Subjects chosen were between the
ages 18-40 and were not currently using alcohol, and/or illicit or prescribed drugs in
order to reduce adverse drug-drug interactions.40
General Study Design
This study is a double-blind, randomized, placebo-controlled trial to evaluate the
safety and efficacy of Lokitonin in patients with IED.41 All eligible patients were assigned
a placebo for a two week lead-in phase so that behavioural scores obtained in this period
could serve as the subjects’ placebo-control baselines for subsequent assessments.
Following this phase, the double-blind method of distribution was used to randomly
distribute Lokitonin to fifty subjects, and the placebo to the other fifty subjects. Subjects
took Lokitonin once daily for a duration of 12 weeks and underwent weekly behavioural
assessments.41 To confirm that the patients were taking Lokitonin as prescribed, a
routinely measurement of Lokitonin in blood plasma was obtained. At week 4 of the
treatment, the effectiveness of Lokitonin was evaluated in patients that received
Lokitonin. When the average OAS-M aggression scores in the previous 2 weeks did not
decrease below 25% of the patient’s average placebo-control baseline OAS-M aggression
score, then the dose of Lokitonin was raised. At week 8, the changes in OAS-M
aggression scores were reevaluated under the same criteria as stated for week 4, and
Lokitonin was increased to its maximum dose when a decrease below 25% of the
patient’s average placebo-control baseline OAS-M aggression score was not observed.41
Method
The efficacy of Lokitonin in reducing impulsive aggressive behaviour was
measured by employing multiple psychiatric assessments. The following behavioural
assessments were used: State aggression and irritability was measured using the OASM. The Clinical Global Impressions-Improvement scale (CGI-I) was used to measure the
patient’s clinical response to the treatment and their improvement in the severity of
their mental illness at the time of assessment.42 We refrained from subjecting patients to
artificial anger-inducing stimuli as a measure of aggressive responsiveness, in order to
comply with ethical and safety regulations.
Results
Subjects who received Lokitonin treatment scored lower OAS-M aggression and
irritability scores at each time point when compared to subjects receiving placebo
treatment. Subjects who received Lokitonin treatment scored lower on the CGI-I scale at
-9-
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
each time point when compared to the placebo.41 See Figure 7 for OAS-M aggression
scores of the appendix.
Conclusion
A sustained reduction in OAS-M aggression, OAS-M irritability, and CGI-I scores
at each time point suggested that Lokitonin treatment reduces impulsive aggression in
IED patients and has subsequently caused them to become more stable where less than
50% of IED patients experienced full or partial remission when treated with Lokitonin.41
Justifying Our Presence
There is no place in this world for wrath. Wrathful behaviours often result in violence,
and violent acts account for approximately 1.43 million deaths worldwide each year. 2
The introduction of Lokitonin into the market would augment the lives wrathful people,
their victims, and all those surrounding. Currently, there is no specific pharmaceutical
treatment available for patients with IED, the target population of our drug. As a result,
individuals who are clinically diagnosed with IED, are often prescribed mood stabilizers,
anti-anxiety pills, anticonvulsants and/or antidepressants.43 As these prescriptions are
not intended to treat impulsive aggression specifically, individuals experience many
adverse side effects. Therefore there is a pressing need for a drug such as Lokitonin,
which is designed specifically to treat impulsive aggression. One of the greatest benefits
of Lokitonin is its high selectivity for the 5-HT1A and 5-HT2A receptors in the OFC.
Drug selectivity is a crucial element of drug design, especially when targeting a receptor
as widespread as that of serotonin. Ensuring binding in the OFC will limit side effects
and ensure the drug is performing its intended function optimally. Although side effects
will be minimal, we recognize that all drugs generate some degree of undesired effects.
To address this issue, we are currently conducting long term clinical tests to ensure drug
safety in regular users of Lokitonin. For example, one safety element being explored is
the notion that even with the use of a hydrophilic matrix gel and nanotechnology, it is
possible, though unlikely, that these precautions may not effectively shield the drug
from the 5-HT2A receptors in the gastrointestinal tract. 44
Further Testing
Since IED has a high incidence of psychiatric comorbidity, 45 IED patients are
often treated with other types of long-term medications. 43 Additional tests should be
done to observe the interactions between Lokitonin and these drugs. This will determine
whether Lokitonin is suitable for patients on simultaneous drug regimens. The
possibility of using Lokitonin to treat other psychological disorders should also be
researched and tested, as we are hoping to eventually expand the target population of
our drug to encompass other aggressive populations and impulsive disorders.
Additionally, Lokitonin must be tested on larger sample groups and over a longer
time period before applying for Food and Drug Administration (FDA) approval. There is
great promise that Lokitonin will soon become a novel and effective treatment for IED
patients.
- 10 -
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
Appendix
Figure 1: The neural pathway of aggressive behaviour. RN = raphé nucleus; OFC =
orbitofrontal cortex; BNST = bed nucleus of stria terminalis; AHA = anterior
hippocampus; PAG = periaqueductal gray.4
Figure 2: Lokitonin binding on 5-HT1A and 5-HT2A receptors. This depicts Lokitonin’s
possible modes of binding on the orthosteric sites of the serotonergic 5-HT1A and 5HT2A receptors in the orbitofrontal cortex to elicit an anti-aggressive response.
- 11 -
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
Figure 3: Dose-response curve of Lokitonin binding onto the 5-HT2A receptor. This
dose-response curve shows the relationship between the amount of dosage
administered and the concentration of IP3, a secondary messenger molecule, released
through the phosphoinositide secondary messenger system when 5-HT2A receptors are
activated. The negative control test showed high IP3 release due to the agonizing
effects of 251-NBOMe, while the positive control test showed minimal IP3 release due
to the antagonizing effects of nefazodone.
Figure 4: Dose-response curve of Lokitonin binding onto the 5-HT1A receptor. This
dose-response curve shows the relationship between the amount of dosage
administered and the concentration of cAMP, a secondary messenger molecule,
- 12 -
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
released via activation of the 5-HT1A receptor. The negative control test showed low
cAMP release due to the antagonizing effects of WAY-100635, while the positive control
test showed high cAMP release due to the agonizing effects of F 11440
Figure 5: The image above illustrates the distribution of 5-HT1A and 5-HT2A receptors in
the brain, focusing on the orbitofrontal cortex, where square markers and circle markers
show the highly dense colocalization of 5-HT1A and 5-HT2A receptors. The images also
demonstrate that Lokitonin successfully passes the BBB and binds primarily to 5-HT1A and
5-HT2A receptors in the orbitofrontal cortex.46
- 13 -
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
Figure 6: Number of bites and flank marks performed by male experimental mice after
intruder placed inside home cage for 10 minute duration, with microinjection of Lokitonin or
saline solution of 20% dimethyl sulfoxide in the OFC. Although the black colour indicates
the number of bites and flank marks performed by the male experimental mice after
microinjection of Lokitonin, no black is represented on the graph because little to no attacks
were made by the Lokitonin-injected mice.33
- 14 -
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
Figure 7: Visitwise and Endpoint OAS-M Aggression Scores in Lokitonin- and PlaceboTreated Subjects with Intermittent Explosive Disorder.This graph represents the results of
the double-blind randomized placebo test that was done on Lokitonin. The data shows that
patients taking Lokitonin exhibited less aggression over the span of 12 weeks based on the
OAS-M Aggression Score.41
- 15 -
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
SECTION 4: Annotated References
(1 ) Chekhonin VP, Chistiakov DA, Pavlov KA. Genetic determinants of aggression and
impulsivity in humans. Polish Academy of Sciences. [Online] 2012;53: 61-82. Available
from: doi: 10.1007/s13353-011-0069-6. [Accessed 26th February 2012].
This article is an overview of the genetic and non-genetic factors that affect
the expression of aggression in humans. It was utilized specifically in
detailing the factors resulting in reactive aggression. The article characterized
reactive aggression by its relationship to emotional balance and the failure to
maintain it. It was therefore valuable in the construction of our overall definition
for wrath in molecular terms, and gave justification for confining this definition
to the limbic system and its associated pathways.
(2 ) Siever, LJ. Neurobiology of aggression and violence. The American Journal of
Psychiatry. [Online] 2008;165: 429-442. Available at: doi:
10.1176/appi.ajp.2008.07111774. [Accessed 14th March].
This article outlines the neurobiological mechanisms underlying impulsive
aggressive behaviours, stating that impulsive aggression arises from the failure of
the orbitofrontal cortex to modulate the aggressive drive of the amygdala.
Although the secondary role other neurotransmitters play in modulating
aggression is discussed, this journal demonstrates that the lack of serotonergic
facilitation in the orbitofrontal cortex is the primary reason the orbitofrontal
cortex is unable to suppress aggressive impulses from the amygdala. Several
functional brain imagining studies were discussed that show decreased activation
of the orbitofrontal cortex during an unrestrained aggressive scenario in
individuals with recurrent episodic violent behaviours compared to healthy
participants. Thus, this journal provided us with a clear understanding of the
pathway and the key molecules involved in impulsive aggression. We modeled
our pathway of impulsive aggression off of the information and pathway
presented in this article.
(3) Siegel A, Bhatt S, Bhatt R, Zalcman S. The neurological bases for development of
pharmacological treatments of aggressive disorders. Current Neuropharmacology.
[Online] 2007; 5(2): 135-147. Available at:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2435345/ [Accessed 20th March
2012].
This review article was used to help describe the neural pathway for
aggressive behaviour. The PAG is the final destination of the descending
pathway and the dorsal PAG uses signals that are sent by the anterior medial
hypothalamus. These signals lead to the efferent projections that impact
somatomotor and autonomic mechanisms of impulsive aggression. This
information helped determine which molecules were involved in the aggression
pathway, and in turn, what specific mechanisms to investigate when preventing
wrathful behaviour. This source was particularly valuable because it provided the
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Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
mechanisms for different types of aggression, thus allowing us to find the
neurological pathway specific to wrath as we had defined it (i.e. reactive
aggression).
(4 ) Nelson RJ, Trainor BC. Neural mechanisms of aggression. Nature. [Online] 2007;8:
536-546. Available at:
http://psychology.ucdavis.edu/labs/trainor/Nelson_Trainor2007.pdf. [Accessed 18th
March 2012].
This review article outlines the neural mechanism of aggression as well as the
potential role that several different molecules (such as serotonin, dopamine,
GABA, noradrenaline, testosterone, nitric oxide and MAO) have in inhibiting or
completing the wrath pathway. This article was gave us a general understanding
of the different molecules involved and provided clear explanations of recent
studies performed for each of the listed molecules. It also stated explicitly how
significant each molecule’s role was in stimulating or inhibiting aggressive
behavior, thereby facilitating our process of picking a target molecule. This article
is a credible source as it was published in the well established journal Nature.
(5) Simpson, K. The role of testosterone in aggression. McGill Journal of Medicine.
[Online] 2001;6: 32-40. Available at:
http://www.med.mcgill.ca/mjm/v06n01/v06p032/v06p032.pdf. [Accessed 19th March
2012].
This article was utilized in determining the specific mechanism by which
testosterone modulates the aggression pathway. It indicated that steroid
hormones, such as testosterone, regulate the opening and closing of
membrane-bound ion channels. Thus, testosterone plays an auxiliary role in the
release of neurotransmitters such as serotonin, which have a more direct
involvement in modulating aggressive behaviours.
(6 ) de Almeida RMM, Ferrari PF, Parmigiani S, Miczek KA. Escalated aggressive
behavior: Dopamine, serotonin and GABA. European Journal of Pharmacology.
[Online] 2005;526(1–3): 51-64. Available at: doi:
http://dx.doi.org/10.1016/j.ejphar.2005.10.004. [Accessed 14th March 2012].
This review article details the involvement of dopamine, serotonin and GABA in
aggression pathways in the brain. It was utilized primarily as a reference, which
described the interplay of these neurotransmitters, and explained specific actions
of their receptor subtypes. From this article we also utilized summaries of the
observed correlations between cortical levels of these neurotransmitters and the
resultant aggression responses observed-- both in murine and human
experimental trials.
(7) Seo D, Patrick C, Kennealy P. Role of serotonin and dopamine system interactions in
the neurobiology of impulsive aggression and its comorbidity with other clinical
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Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
disorders. Aggressive and Violent Behavior. [Online] 2008;13(5): 383-395. Available
from: doi: http://dx.doi.org/10.1016/j.avb.2008.06.003. [Accessed 19th March 2012].
This article summarized the role of dopamine in the wrath pathway which was
useful for us since dopamine was one of our proposed target molecules. It
outlined several animal studies where rodents with elevated dopamine levels also
exhibited more aggressive behavior before, during, and after fights. Moreover, it
was found when coupled with a serotonin deficiency, dopamine triggers
impulsive aggression in mice. Thus, it is unclear whether the heightened
aggression observed in these animal studies resulted from the serotonin
deficiency or the higher levels of dopamine, causing us to keep our attention on
serotonin as the primary neurotransmitter, whose function in aggression
modulation is distinguished. The journal Aggression and Violent Behavior was
used since it addresses a multi-disciplinary range of topics regarding pain and
aggression with examples such as homicide, family violence and genetic
predispositions.
(8 ) Hollander E, Tracy KA, Swann AC, Coccaro EF, McElroy SL, Wozniak P,
Sommerville KW, Nemeroff CB. Divalproex in the treatment of impulsive aggression:
Efficacy in cluster B personality disorders. Neuropsychopharmacology. [Online]
2003;28: 1186–1197. Available at: doi: 10.1038/sj.npp.1300153. [Accessed 18th March
2012].
This article studied the effectiveness of the drug divalproex in treating impulsive
aggression by comparing placebo effects versus drug effects after a twelve week
clinical trial. The study stated that its target population included individuals
diagnosed with intermittent explosive disorder (IED) and that such patients
displayed lower levels of serotonergic activity in the OFC. From this, we
extrapolated that people who have low levels of serotonin in the OFC display
higher levels of aggression. Thus, we used the Serotonin Deficiency Hypothesis as
a component of our definition of wrathful individuals. This source is credible as it
was published in Neuropsychopharmacology which is a journal branched off of
the highly-reputable Nature.
( 9) Monti JM, Monti D. Role of dorsal raphe nucleus serotonin 5-HT1A receptor in the
regulation of REM sleep. Elsevier. [Online] 2000;66(21): 1999-2012. Available from:
doi: http://dx.doi.org/10.1016/S0024-3205(99)00649-9. [Accessed 19th March 2012].
This source provided a pressing reason not to target the dorsal raphe
nucleus despite the high concentrations of serotonin receptors which have an
important role in our aggression pathway. Through vigorous testing, the article
demonstrated that varying doses of serotonin agonist led to the alteration of sleep
cycles, thus disturbing rapid eye movement (REM) sleep cycles. The disturbance
of sleep cycles correlates to irritability, which increases the likelihood of
impulsive aggression. In attempting to cure aggression, disturbing the sleep cycle
and causing irritability was clearly not a viable option. This article was from the
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Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
journal Life Sciences, and cites over 80 other academic references.
(10 ) Jasinska AJ, Lowry CA, Burmeister M. Serotonin transporter gene, stress and
raphe–raphe interactions: A molecular mechanism of depression. Trends in
Neuroscience. [Online] 2012;35(4): 209-270. Available at: doi:
http://dx.doi.org/10.1016/j.tins.2012.01.001. [Accessed 18th March 2012].
This article was used to examine the role of serotonin in the dorsal raphe
nucleus(DRN). The article demonstrated that the DRN has the highest
density of serotonin receptors in the brain as it is responsible for projecting
serotonin throughout the brain. It also acknowledged that there is a high
concentration of 5-HT1A autoreceptors in the DRN. This article enlightened us
with the knowledge that since the DRN plays such a crucial role in facilitating
serotonergic neurotransmission throughout the brain, it would not be the most
ideal target for our drug as targeting serotonin receptors in the DRN would
impact serotonin levels throughout many regions of the brain and thus have
various side effects. This source cites 99 other academic journals, supporting all
of the expressed facts. The journal, Trends in Neuroscience, is specific to the
topic of discussion, and therefore displays how thorough this article is.
(11 ) Pytliak M, Vargova V, Mechirova V, Felsoci M. Serotonin receptors: from molecular
biology to clinical applications. Physiological Research. [Online] 2011;60: 15-25.
Available at: http://www.ncbi.nlm.nih.gov/pubmed/20945968. [Accessed 18th March
2012].
This article outlines the function of the 5-HT1B receptor in the pathway of
impulsive aggression and states that 5-HT1B agonists cause an increase of
aggressive behavior. It also outlined the different areas where 5-HT1B
receptors are located in the brain as well as the diverse effects that these
receptors initiate depending on where they are located. The role of the 5-HT1B
receptor as both an autoreceptor and its secondary role in controlling secretion of
other neurotransmitters was discussed. Such a piece of information was
important in our process of eliminating 5-HT1B receptor as our target receptor
since we wanted to find a class of serotonergic receptors that was as location and
function specific as possible, in order to ensure the selectivity of our drug. This
article is credible since it cites over 72 sources and was published only a year ago;
therefore, the findings presented in it are upon the most up-to-date.
(12) Zald D, Rauch S. The Orbitofrontal Cortex. London: Oxford University Press; 2006.
Since the orbitofrontal cortex was the loci of intervention of our drug, it was
necessary for us to learn as much as we could about this brain region. This book
was a very in-depth resource, which described the functions, neurophysiology,
pathways, and related disorders pertaining to this region. Not only did it allow us
to develop a deeper understanding of the intervention site of Lokitonin, but it
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Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
allowed us to infer the consequences of tampering with this brain region, the
side-effects that could occur, and the different biochemical involved. One of the
most useful aspects of this book was its detailed description of the receptors
found in this brain region with special emphasis on the 5-HT2A. This book is
credible as it is published by a well-known publishing company, the Oxford
University Press. In addition, its authors are David Zald, an associate professor of
psychology and psychiatry of Vanderbilt University, whose articles have been
cited 5626times, along with Scott Rauch, the Associate Chief of Psychiatry for
Neuroscience Research at Harvard Medical School.
(13) Carli M, Marta B, Roberto I, Claudia B. Dissociable Contribution of 5-HT1A and 5HT2A Receptors in the Medial Prefrontal Cortex to Different Aspects of Executive
Control such as Impulsivity and Compulsive Perseveration in Rats.
Neuropsychopharmacology. [Online] 2006; 31: 757–767. Available from:
http://www.nature.com/npp/journal/v31/n4/full/1300893a.html [Accessed 9th March
2012].
The following article was highly valuable for it used in situ hybridization
histochemistry to determine the distribution of serotonin receptors 5-HT1A and
5-HT2A in the prefrontal cortex (PFC) of rats. Since we wanted to target both of
these receptors in area 11 of the PFC, it was necessary for us to verify the
localization of these receptors for two reasons. Firstly, we had to ensure that at
least one of the two receptors was found in high density in the OFC. Secondly, we
had to ensure that there was close enough spatial overlap between the two
receptors so that a bidentate ligand could be created. Numerous literatures
suggest that the anatomy of the rat brain is very similar to that of a human
therefore it was valid for us to apply the conclusions gathered from this study into
our own project. By using histochemical techniques, the study concluded that
approximately 80% of these receptors are co-localized in the serotonergic
neurons of the prefrontal cortex. Since the OFC is one region of the prefrontal
cortex, we were able to deduce, with confidence, that the bidentic mechanism of
our drug would be a viable one.
(14 ) Rosell D, Thompson J, Slifstein M, Xu X, Frankle W, New A, Goodman M,
Weinstein S, Laruelle M, Abi-Dargham A, Siever L. Increased Serotonin 2A Receptor
Availability in the Orbitofrontal Cortex of Physically Aggressive Personality Disordered
Patients. Biological Psychiatry. [Online] 2010; 67(12): 1154-1162. Available from: doi:
10.1016/j.biopsych.2010.03.013. [Accessed 3rd March 2012].
This article laid the foundation for our drug’s mechanism and was perhaps
one of the most important articles that we consulted when laying out the
framework of our drug. The article studied only IED patients, which was of
great value since they were the designated target population of Lokitonin.
Furthermore, the study focused specifically on the orbitofrontal cortex, which
was also the intervention locus of Lokitonin. For these two reasons, we felt that it
was reasonable for us to extrapolate the results from this study and apply them to
our own drug design. This article used positron emission tomography and
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Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
radiolabelled 5-HT2A receptor antagonists to study the availability of these
receptors in the OFC. Not only did the study find high numbers of 5-HT2A
receptors in the OFC, but they also found that these numbers were higher in IED
patients than in non-aggressive individuals. Moreover, Rosell et al. found that
activation of these receptors stimulated aggressive behaviour. The results from
this study provided the evidence we needed in favour of administering a 5-HT2A
antagonist in order to inhibit aggressive behaviour in IED patients. This study
also provided evidence that our drug would provide a highly localized response in
the OFC since the 5-HT2A receptor was most densely found in this brain region.
(15) Canton H, Verrièle L,Millan MJ. Competitive antagonism of serotonin (5-HT)2C
and 5-HT2A receptormediated phosphoinositide (PI) turnover by clozapine in the rat: A
comparison to other antipsychotics. Neuroscience Letters. 1994;181(1-2): 65-68.
[Online]. Available from: doi:10.1016/0304-3940(94)90561-4 [Accessed March 28,
2012].
This article describes a study looking into the competitive and orthosteric
antagonism of the 5-HT2A and 5-HT2C receptors by clozapine in the rat. It
employs the in vitro model of 5-HT-induced phosphoinositide (PI) turnover in
rat choroid plexus for the 5-HT2C receptors and the frontal cortex for the 5
HT2A receptors. The potency of clozapine is found to be relatively high, further
justifying why Lokitonin includes an orthosteric antagonist for the 5-HT2A
receptors. This article is credible as it is in the journal Neuroscience Letters
which is published by Elsevier, a highly renowned publishing company for
medical and scientific literature.
(16) Heusler P, Palmier C, Tardif S, Bernois S, Colpaert F, Cussac D. [3H]-F13640, a
novel, selective and high-efficacy serotonin 5-HT1A receptor agonist radioligand.
Naunyn Schmiedeberg’s Archives of Pharmacology. 2012;382(4): 321-330. [Online].
Available from: doi:10.1007/s00210-010-0551-4 [Accessed March 28, 2012].
This journal article describes F13640, a potent and high-efficacy 5-HT1A receptor
agonist, and its analgesic potential in animal models. It also exerts its effects via
binding to the orthosteric site. This validates Lokitonin as an orthosteric 5-HT1A
receptor agonist, as it is evidently shown in this article that there exist orthosteric
drugs that specifically act on 5-HT1A receptors. This article is reputable as it is
published by a journal edited on behalf of the world-renowned German Society of
Experimental and Clinical Pharmacology and Toxicology.
(17) Maderuelo C, Zarzuelo A, Lanao J. Critical factors in the release of drugs from
sustained release hydrophilic matrices. Journal of Controlled Release. [Online] 2011;
154(1): 2-19. Available from:
http://www.sciencedirect.com/science/article/pii/S0168365911002124 [Accessed 15th
March 2012].
Since we wanted Lokitonin to have twenty-four hour effects, we felt it
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Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
necessary to couple the drug with some sort of timed-release technology. This
article provided a very comprehensive analysis of hydrophilic matrices as an
inexpensive and effective method of sustained-release drug delivery for orally
administered medication. One of the most significant points highlighted in this
paper was the variability of hydrophilic matrices. These matrices can be
customized by manipulating factors such as size, membrane permeability,
material, and weight to ensure specific pharmacokinetic properties. For
Lokitonin, the hydrophilic matrix controls the drug’s rate of dissolution in the
gastrointestinal tract and allows for sustained-release of the drug into the
bloodstream. The widespread use and cost-efficiency of hydrophilic matrices
makes them a suitable and reliable choice for oral timed-release drug delivery. All
in all, the article provided concrete evidence in favour of our choice to use a
hydrophilic matrix over other forms of sustained-release drug delivery.
(18) Moodley K, Pillay V, Choonara YE, du Toit LC, Ndesendo VM, Kumar P, Cooppan S,
Bawa P. Oral drug delivery systems comprising altered geometric configurations for
controlled drug delivery. International Journal of Molecular Sciences. [Online] 2012;
13(1): 18-43. Available from: http://www.ncbi.nlm.nih.gov/pubmed/22312236
[Accessed 22nd March 2012].
In order to ensure that Lokitonin would produce a long-lasting twenty-four hour
effect in humans, we decided that it would be of great value to have the drug
follow a zero-order release mechanism. This article provided great insight into
the advantages and desirability of zero-order kinetics in pharmacology, as well as
the difficulty encountered in establishing such optimal conditions. Moodley et al
did, however, describe a plausible method by which near zero-order drug release
could be obtained by combining hydrophilic matrices with polymerized materials.
Since hydrophilic matrices allow the drug to dissolve at a rate that is independent
of the drug concentration and the use of polymerized coating slows the rate of
water uptake, the combination of the two factors creates the ideal conditions for
near zero-order pharmacokinetics.
(19 ) Lipinski CA, Lombardo F, Dominy BW, Feeney PJ. Experimental and
computational approaches to estimate solubility and permeability in drug discovery and
development settings. Advanced Drug Delivery Reviews. [Online] 1997;23: 3-25.
Available from:
http://www.sciencedirect.com/science/article/pii/S0169409X96004231 [Accessed 1st
April 2012].
Lipinski’s rule of 5 predicts that good drug absorption or permeation is more
likely when there are a) less than 5 H-bond donors and 10 H-bond acceptor
groups in the molecule; b) the molecular weight is less than 500; and c) the
compound’s lipophilicity, expressed as the octanol-water partition coefficient,
Log P, is less than 5. The rule of 5 is used to test the physio-chemical properties of
a drug and determines whether it would function well as an orally active drug.
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Group
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TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
This rule is essential for the development of a successful oral drug and was
formulated by Christopher Lipinski in 1997. This is a reliable source for it is a
journal article which uses proper referencing throughout and was cited 5245
times.
(20) Bhaskar S, Tian F, Stoeger T, Kreyling W, Fuente J, Grazu V, et al. Multifunctional
nanocarriers for diagnostics, drug delivery and targeted treatment across blood-brain
barrier: perspectives on tracking and neuroimaging. Particle and Fibre Toxicology.
[Online] 2010; 7(3): 73-92. Available from:
http://www.particleandfibretoxicology.com/content/7/1/3 [Accessed 21st March 2012].
The following article provided a very detailed review of nanocarriers as a
potential method of drug transport across the blood-brain barrier (BBB). The
advantages of this nanotechnology include small size, increased drug
stabilization, increased blood plasma solubility, and high delivery to the target
organ. Furthermore, the article provided an in-depth explanation of
nanocarrier functionalization – a process by which nanotubes are combined with
chemical functional groups to ensure high selectivity for a specific target organ.
This process allows nanotechnology to target virtually any region in the body. In
order to test the functionalized nanotechnology, fluorescent imaging is used to
visualize the nanocarrier and its transportation through the body to ensure that it
is in fact arriving at the target organ. All in all, this article facilitated our decision
to choose nanotechnology over alternate modes of drug delivery such as
liposomes. It is a reliable source as the article is published by a journal with a
high impact factor of 4.91.
(21) Maynard JA, Lindquist NC, Sutherland JN, Lesuffleur A, Warrington AE, Rodriguez
M, Oh S-H. Next generation SPR technology of membrane-bound proteins for ligand
screening and biomarker discovery. Biotechnology Journal. [Online] 2009; 4(110):
1542-1558. Available from:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2790208/?tool=pubmed [Accessed 1st
April 2012].
This journal article gave a detailed description about SPR technology and its
technological use. SPR technology measures affinity and binding kinetics
between capture molecules immobilized on a gold surface as well as target
molecules in the liquid by monitoring the change in behavior of surface plasmon
(SP) waves in real time. SP waves are a rippling motion of the gold’s conduction
electrons at the interface between gold and the sample solution. It propagates
along the gold-liquid interface and its wavelength changes when encountering a
thin layer of biomolecules bound to the gold film. In particular, the nanopore
array would be useful for our experiment for it supports free-standing lipid
bilayers over nanopores. These lipid bilayers are able to mimic the natural
biological membrane and therefore, maintain their functionality. GCPR may also
be studied using this technology. SPR kinetic assays, provide many advantages
over fluorescent labelling methods such as the ability to determine ligand-analyte
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Group
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TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
binding kinetics without the interference of probes within the binding
interactions. Also, binding kinetics and affinities can be measured directly as
opposed to only knowing that binding events occur. This is an journal article
published by Biotechnology and was therefore peer-reviewed to ensure its
accuracy.
(22) Schaasfoort RBM, Tudos AJ (eds.). Handbook of surface plasmon resonance. The
Royal Society of Chemistry, Cambridge; 2008. pp.1-39.
This source provided the direct detection methodology in which our
Surface Plasmon Resonance (SPR) experimentation was based off of. It
thoroughly explains the theory behind SPR technology, its history and
design, and gives a detailed explanation on how SPR technology works. It
provides step-by-step instructions on how to perform an SPR Assay, which
was used in our experiments, as well as how to analyze the calibration curve
produced by this process. It stated the characteristics of high affinity
analytes in terms of KA and KD rates, allowing us to ensure the high
affinity of Lokitonin to the 5-HT2A receptor. This book is published by the Royal
Society of Chemistry and is therefore, a very reliable source.
The methodology of the direct detection method is the following: Capture
molecules, serotonin 5-HT1A and 2A receptors, or ligands, were permanently
immobilized on the sensor surface, a thin gold film, previous to the
measurement. Then, the sensor surface was immersed with a buffer
solution composed of a liquid solution containing analyte, Lokitonin. This was
the baseline - because capturing had yet to occur. The analyte solution was then
injected, and the analyte was captured on the surface. Adsorption kinetics of the
analyte molecule was measured. Next, the buffer was injected onto the sensor.
The accumulated mass was measured from the SPR response and once the
dissociation of the analyte began, the kinetics of the dissociation process was also
measured. A regeneration solution was then injected, breaking the binding
between analyte and ligand. The target analytes were quantitatively removed
while the ligands remained on the sensor. This analysis cycle was repeated
hundreds to thousands of times.
(23 ) Urban JD, Clarke WP, von Zastrow M, Nichols DE, Kobilka B, Weinstein H,
Javitch JA, Roth BL, Christopoulos A, Sexton PM, Miller KJ, Spedding M, Mailman RB.
Functional selectivity and classical concepts of quantitative pharmacology. The journal
of pharmacology and experimental therapeutics. [Online] 2007; 320(1): 1-13. Available
from: http://jpet.aspetjournals.org/content/320/1/1.full [Accessed 24th March 2012].
This source was used to determine that 5-HT2 receptors are coupled to a
phosphoinositide secondary messenger system. This system involves the
stimulation of a G protein after an agonist binds to a receptor. This activates
phospholipase C (PLC), which in turn cleaves PIP2 to yield inositol phosphate
(IP3) and diacylclycerol, secondary messenger molecules, modulating
- 24 -
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
intracellular calcium (Ca^2+). This supports the measuring of intracellular IP3
levels with immunohistochemistry. It is a credible source for it is published in
The Journal of Pharmacology and Experimental Therapeutics, and uses
appropriate referencing throughout.
(24) Ettrup A, Hansen M, Santini MA, Paine J, Gillings N, Palner M, Lehel S, Herth
MM, Madsen J, Kristensen J, Begtrup M, Knudsen GM. Radiosynthesis and in vivo
evaluation of a series of substituted 11C-phenethylamines as 5-HT2A agonist PET
tracers. European Journal of Nuclear Medicine and Molecular Imaging. [Online] 2011;
38: 681-693. Available from:
http://www.springerlink.com/content/960707jg63pg36v8/fulltext.pdf [Accessed 1st
April 2012].
This source states that 251-NBOMe is a superpotent and selective 5-HT2A
receptor agonist and therefore, suitable in the negative control test when
measuring IP3 concentrations in the preclinical study measuring second
messenger molecule concentrations. This is a reliable source for it is
published by a well-known journal, is peer-reviewed and uses proper
referencing.
(25 ) Tanimura A, Morita T, Nezu A, Shitara A, Hashimoto N, Tojyo Y. The use of FRET
based biosensors for the quantitative analysis of inositol 1,4,5-triphosphate dynamics in
calcium oscillations. The Journal of Biological Chemistry. [Online] 2009; 284: 89108917. Available from: http://www.jbc.org/content/284/13/8910 [Accessed 2nd April
2012].
Inositol 1,4,5-triphosphate (IP3) is an intracellular messenger molecule
released upon agonist binding to the serotonin 5-HT2A receptor, produced
by the hydrolysis of phosphatidyl-inositol 4,5-biphosphate (PIP2) by
phospholipase C. IP3 is responsible for eliciting Ca2+ signals. IP3-R-based
FRET biosensors consists of the ligand-binding domain of IP3R and the
fluorescent proteins CFP and YFP. An example of a IP3-R-based FRET
biosensor is LIBRA, which has a high selectivity for IP3. This article
provides a testing method to quantitatively measure intracellular IP3
concentration change in single living cells, validating our experimental
procedure. This study was conducted at the University of Hokkaido in Japan and
was published by The Journal of Biological Chemistry. The article is peer
reviewed and uses appropriate referencing throughout, thereby ensuring that
accurate and quality information is being provided.
(26) Stahl S. Depression and Bipolar Disorder: Stahl’s Essential Psychopharmacology,
3rd ed. Cambridge University Press, Cambridge; 2008. pp. 110-125.
This source states that the 5HT1A receptors are part of a second messenger
system that utilizes cAMP. It also verifies that Nefazodone is an antagonist of
serotonin 5HT2A receptors and therefore, suitable in the positive control test
- 25 -
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
when measuring IP3 concentrations in the preclinical study measuring second
messenger molecule concentrations. This is a book published by the Cambridge
University Press, a world-renowned publishing house and therefore can be
trusted to provide accurate information.
(27 ) Borner S, Schwede F, Schlipp A, Berisha F, Calebiro D, Lohse MJ, Nikolaev VO.
FRET measurements of intracellular cAMP concentrations and cAMP analog
permeability in intact cells. Nature Protocols. [Online] 2011; 6:427-438. Available from:
http://www.nature.com/nprot/journal/v6/n4/full/nprot.2010.198.html [Accessed 2nd
April 2012].
Radiometric fluorescence resonance energy transfer (FRET) imaging allows the
real-life measurements of second messengers such as cAMP in living cells. FRET
occurs between a pair of different fluorophores attached to one or two protein
molecules in order to report protein-protein interactions. FRET measurements
are performed by radiometric imaging of biosensors’ fluorescence, and the
experimental data are presented in FRET ratio traces. FRET biosensors include
cyan (CFP) and yellow fluorescent proteins (YFP), and are used to measure the
relative fluorescence of the donor and acceptor fluorophores. These fluorophores
are genetically fused to the catalytic subunits of kinase, a cAMP dependent
enzyme. FRET allows the measurement of relative changes in cAMP levels. This
source provides a step by step method to measure cAMP concentrations using
FRET technology. Nature Protocols is an online journal that is of high quality
and peer-reviewed content and can therefore, be trusted as a reliable source.
(28 ) Koek W, Patoiseau JF, Assie MB, Cosi C, Kleven MS, Dupont-Passelaigue E, et al. F
11440, a potent, selective, high efficacy 5-HT1A receptor agonist with marked anxiolytic
and antidepressant potential. Journal of Pharmacology and Experimental
Therapeutics. [Online]. 1998; 287(1): 266-283. Available from:
http://jpet.aspetjournals.org/content/287/1/266.long [Date Accessed: 2 April 2012].
This source confirmed that F 11440 is a potent 5-HT1A receptor agonist and can
therefore be used as a positive control in our experimental procedure testing the
concentration of cAMP release.
( 29) Fletcher A, Forster EA, Bill DJ, Brown G, Cliffe IA, Hartley JE, Jones DE,
McLenachan A, Stanhope KJ, Critchley DJP, Childs KJ, Middlefell VC, Lanfumey L,
Corradetti R, Laporte A, Gozlan H, Hamon M, Dourish CT. Electrophysiological,
biochemical, neurohormonal and behavioural studies with WAY-100635, a potent,
selective and silent 5-HT1A receptor antagonist. Behavioural Brain Research. [Online]
1996; 73: 337-353. Available from:
http://www.sciencedirect.com/science/article/pii/0166432896001180 [Accessed 1st
April 2012].
This article confirms that WAY-100635 is a potent and selective 5-HT1A
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Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
receptor antagonist, and can therefore, be used as a negative control when testing
or the concentration of cAMP release in our experimental
procedure. It is a peerreviewed article that uses proper referencing.
(30 ) Dillon KA, Gross-Isseroff R, Israeli M, Biegon A. Autoradiographic analysis of
serotonin 5-HT1A receptor binding in the human brain postmortem: effects of age and
alcohol. Brain Research. [Online] 1991; 554(1-2): 56-64. Available from:
http://www.sciencedirect.com/science/article/pii/000689939190171Q [Accessed 2nd
April 2012].
By using radiography on post-mortem brains, it is possible to see the
distribution of receptors within a particular part of the brain. A radiotracer
was placed onto Lokotonin in order to confirm whether or not the drug was
indeed targeting the orbitofrontal cortex. This source was an example of how
a radiotracer could be put onto a known molecule of 8-OH-DPAT, a known 5
HT1A agonist, in order to identify areas of distribution of a particular receptor.
This is a reliable source because it comes from notable academic institutions such
as the Department of Psychiatry at the NYU Medical Center and the Department
of Neurobiology at the Weizmann Institute of Science.
(31) Lesch KP, Merschdorf. Impulsivity, Aggression, and Serotonin: A Molecular
Psychobiological Perspective. Behavioural Sciences and the Law. [Online] 2000;18(5):
581-604. Available from: doi: 10.1002/1099-0798(200010)18:5<581::AIDBSL411>3.0.CO;2-L [Accessed 28th March 2012].
This journal article reviews studies that have been done to investigate into how
the genetic variability in serotonergic expression leads to inappropriate
aggressive behaviour. In one section, it specifically describes the role of serotonin
receptor subtypes in impulsive and aggressive behaviour. In the animal testing of
the methodology used to test the effects of Lokitonin, isolation and resident
intruder paradigms were used to induce aggression in mice so that the anti
aggressive effects of Lokitonin could be tested. The article explains how impulsive
and aggressive behaviour of 5-HT1B knockout mice could be assessed through
isolation and subsequent contact with to an intruder mouse. This justified why
the combination of these two paradigms were used to induce impulsive
aggression in the mice. This article is a credible source since it was published in a
peer-reviewed journal that provides current in-depth information from around
the world on topics related to the law and behavioural sciences.
(32) Olivier B, Young LJ. Animal models of aggression. In: Davis, Charney, Coyle,
Nemeroff (Eds.), Neuropsychopharmacology: The Fifth Generation of Progress.
Philadelphia: Lippincott Williams and Wilkins; 2002. pp. 1699-1706.
This book excerpt explains the procedures of how different types of aggression
can be induced in animals such as mice. It also goes into detail regarding the pros
and cons of each aggression model. This excerpt helped to justify why we chose
the resident-intruder and isolation paradigms to induce aggression in the mice.
- 27 -
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
Isolation-induced aggression in mice is proven to accurately predict human
aggression in studies. Similarly, resident-intruder paradigms can be widely
generalized to encompass both humans and rodents. This book is credible as it is
world-renowned and it is the most recent comprehensive work of the American
College of Neuropsychopharmacology.
(33) Delville Y, Mansour KM, Ferris CF. Serotonin blocks vasopressin-facilitated
offensive aggression: Interactions within the ventrolateral hypothalamus of golden
hamsters. Physiology & Behaviour. [Online] 1996;59(4-5): 813-816. Available from:
doi:10.1016/0031-9384(95)02166-3 [Accessed 28th March 2012].
This journal article tests for the anti-aggressive effects of fluoxetine, a
serotonin reuptake inhibitor, in golden hamsters after aggression was
induced via a resident-intruder paradigm. The methodology employed in this
study was one of the ones used in our methodology to test the effects of Lokitonin
in vivo. The study used a bar graph to compare the number of bites and flank
marks on the intruder mice by the control group and the experimental group
treated with fluoxetine. Since both fluoxetine and Lokitonin both enhance the
effects of serotonin in the orbitofrontal cortex, the bar graph was used in our
methodology to display the similar anti-aggressive effects of Lokitonin. This
article is credible as it has been cited over 100 times and is published by the
official journal of International Behavioural Neuroscience Society.
(34) Cervantes MC, Deville Y. Individual differences in offensive aggression in golden
hamsters: a model of reactive and impulsive aggression. Neuroscience. [Online]
2007;150(3): 511-521. Available from: doi:10.1016/j.neuroscience.2007.09.034
[Accessed 28th March 2012].
The study described by this journal article was performed to investigate into the
individual differences in offensive aggression in low aggression and high
aggression golden hamsters. In particular, it relates impulsive aggression in
humans to impulsive aggression in animals and provides support for an animal
model of impulsive aggression. This was done by using a resident-intruder
paradigm, whereby an intruder hamster was placed in the resident’s home cage
for 10 minutes. Aggression being quantified in the form of frequencies and
latencies of bites, flank marks, and contact time.
Normally, the resident-intruder model is used to evoke offensive aggression in
mice, as the mice offensively attack intruders placed in their home cage.
However, this study displayed that offensive aggression in positively correlated
with impulsive aggression. This means that the resident-intruder model can be
used to assess impulsive aggression in our methodology.
Impulsivity was measured by the delay-discounting paradigm, whereby a
delayed-reward-lever and immediate-reward-lever were placed in the mice’s
cages. It was discovered that offensive aggression was positively associated with
impulsivity, as high aggression hamsters displayed a preference for the
- 28 -
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
immediate-reward-lever while low aggression hamsters displayed a preference
for the delayed-reward-lever. Moreover, the high aggression hamsters attacked in
a very repetitive manner, which matches the definition of impulsive aggression,
which is defined by the article as “unplanned, emotionally charged, involving a
loss of behavioural control, and occurring as a reaction to provocation.” This
article is credible as it is published by the Journal of Neuroscience, the official
journal of the Society for Neuroscience. The Society for Neuroscience is the
world’s largest organization of scientists and physicians who research the brain
and nervous system.
(35) Sakaue M, Ago Y, Sowa C, Sakamoto y, Nishihara B, Koyama Y, et al. Modulation
by 5-HT2A receptors of aggressive behaviour in isolated mice. The Japanese Journal of
Pharmacology. 2002:89(1): 89-92. Available from: doi:10.1254/jjp.89.89 [Accessed
28th March 2012].
This article describes a study that explored the relationship between 5-HT2A
receptors and aggression in mice using an isolation-induced aggression model.
The study displayed that the 5-HT2A receptor antagonist, ritanserin, decreased
the total fighting time of mice, consequently reducing isolation-induced
aggression in mice. Since the action of the 5-HT2A antagonist in Lokitonin is
crucial in reducing aggression due to its high affinity and selectivity for the 5
HT2A receptor, this study provides evidence for the results of the in vivo testing
of our methodology, being that Lokitonin decreases isolation-induced aggression.
This article is credible as it is published by the Japanese Journal of
Pharmacology, the official publication of the Japanese Pharmacological Society.
(36) Brunner D, Hen René. Insights into the Neurobiology of Impulsive Behavior from
Serotonin Receptor Knockout Mice. Behavioural Brain Research. 1995;73(1-2): 305.
Available from: doi: 10.1016/0166-4328(96)00119-2 [Accessed 28th March 2012].
The article describes a study that investigates into the concept of impulsivity in
the context of the serotonin and aggression. The study used a knockout mouse
that lacked the 5-HT1B receptor which displayed more impulsive aggression than
the wild-type control. Attack latencies were measured to quantify impulsive
aggression, and attacks having a latency of less than 10 seconds were defined
as impulsive attacks. Therefore, this study confirmed our methodology as only
mice that displayed attack latencies of less than 10 seconds were used for
subsequent testing, as these mice were displaying impulsive behaviour. This
article is credible as it is from a journal published by Elsevier, a highly well known
publishing company that publishes medical and scientific literature.
(37) Brunton L, Chabner BA, Knollmann BC. Goodman & Gilman's The
Pharmacological Basis of Therapeutics, 12e. [Online] New York: McGraw Hill
Professional: 2010. Available from
http://www.accessmedicine.com/content.aspx?aID=16658811 [Date accessed 2nd
April 2012].
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Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
This book describes the procedural protocol for toxicity testing in animals, which
our testing for the long-term side-effects and lethal dose of Lokitonin was based
upon. It also provides the basis for the three phases of human clinical testing in
our methodology. It is a credible source as it is from a highly renowned textbook
whose readership includes physicians, pharmacologists, pharmacists, and
researchers.
(38) Canadian Centre for Occupational Health and Safety. What is an LD50 and LC50?
[Online] Available from: http://www.ccohs.ca/oshanswers/chemicals/ld50.html
[Accessed 28th March 2012].
This webpage informs what the terms “lethal dose” and “LD50” mean and how
they are measured in animals and subsequently calculated for humans. The lethal
dose of a substance is the amount of substance that causes the death of 50% of a
group of test animals. It is generally used to determine the toxicity of a substance.
In our methodology the lethal dose of Lokitonin for the test mice was determined
and a rough estimate of the lethal dose for humans was calculated from the
animal lethal dose. This estimate was used in the clinical trials to provide an
upper limit on the dosage for the IED patients. This article is credible as it is from
a website hosted by the Government of Canada.
(39) Virkkunen M, Goldman D, Nielsen DA, Linnoila M. Low brain serotonin turnover
rate (low CSF 5-HIAA) and impulsive violence. Journal of Psychiatry Neuroscience.
1995;20(4): 271-275. [Online]. Available from:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1188701/?tool=pmcentrez. [Accessed
April 1, 2012].
This article states findings that show reported low brain serotonin turnover
rates in impulsive offenders that behave aggressively while intoxicated. Serotonin
turnover rates were measured by measuring 5-Hydroxyindoleacetic acid (5 HIAA)
(a metabolite of serotonin in the body measured to determine the level of
endogenous serotonin) in cerebrospinal fluid. This is critical because a low 5
HIAA concentration in the cerebrospinal fluid is found to be associated with
increased impulsiveness and impaired control of aggressive behaviours.
Furthermore, it has been found that non-impulsive violent offenders have
relatively low cerebrospinal fluid 5-HIAA concentrations when compared to
healthy volunteers. This information has allowed us to choose IED patients as
Lokitonin’s main target population because its effects raise serotonergic activity
and raising serotonergic activity in the orbitofrontal cortex has the implication of
reducing aggressive behaviour in IED patients. This article is a credible source as
it was published in a well-established journal, the Journal of Psychiatry
Neuroscience, which is a part of the official journal of the Canadian College
of Neuropsychopharmacology.
(40) Swann AC, Hollander E. (Ed). Impulsivity and aggression: Diagnostic challenges
for the clinician. ACCESS Medical Group. 2002. [Online] Available from:
http://www.cene.com/PDFs/D11-1_Impulsivity.pdf [Accessed 1st April 2012].
- 30 -
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
This monograph is sponsored by the ACCESS Medical Group for physicians; it is
also funded by Abbott Laboratories, a global pharmaceuticals and healthcare
products company. The purpose of this monograph is to educate clinicians about
the classifications and causes of, and treatment options for patients exhibiting
symptoms of impulsivity and aggression. Within this monograph, a section was
dedicated to “Measuring and Predicting Impulsive-Aggression” and specifically
talked about the effectiveness of measuring aggression with the Overt Aggression
Scale (OAS). The OAS is divided into four categories of aggression: verbal
aggression, physical aggression against oneself, and physical aggression towards
objects, and physical aggression against other people. The individual is given a
weighted score on each type of aggressive behaviour (physically aggressive
behaviours are weighted more than verbal aggressive acts when given scores).
The scale includes a 16-item report for each aggressive event, where the global
aggression score is obtained by adding the weighted score for the most severe
behaviours in each category. Within Lokitonin clinical trials, the OAS-M (Overt
Aggression Scale-Modified, a modified version of OAS in which the occurrence of
each of the 16 items is rated once a week) was used to assess aggressive and
irritability behaviour at each point in time. This was used in order to assess
Lokitonin’s effectiveness in reducing aggressive behaviours in the four categories,
as indicated by the lowered OAS-M aggression and irritability scores.
( 41) Caccaro EF, Lee RJ, Kavoussi RJ. A double-blind, placebo-controlled trial of
fluoxetine in patients with intermittent explosive disorder. Journal of Clinical
Psychiatry. [Online] 2009;70(5): 653-662. Available from:
http://www.psychiatrist.com/privatepdf/2009/v70n05/v70n0505.pdf. [Accessed 1st
April 2012].
This study is reliable because the methods of assessing aggressive behaviour used
are widely accepted practices in clinical trials. The method used in our clinical
trials is based on an actual pharmacological study of fluoxetine (an SSRI). This
study tested Fluoxetine and its efficacy in reducing antiaggressive effects in
impulsive aggressive IED patients. It shows that Fluoxetine reduces aspects of
impulsive aggressive behaviour in selected DSM-III-R patients with personality
disorders, as assessed by the OAS-M and CGI-I behavioural scores. The same
method of assessment was used in clinical trials to test if Lokitonin is a viable
candidate to reduce impulsive aggressive symptoms in IED patients. In addition,
the validity of this study is evident as it has been cited by 25 other academic
articles.
( 42) Busner J, Targum SD. The clinical global impressions scale. Psychiatry (Edgmont).
[Online] 2007;4(7): 28-37. Available from:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2880930/ [Accessed 1st April 2012].
This study is a reliable source because Clinical Global Impressions (CGI) are used
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Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
in FDA-regulated CNS trials. Also, this study has been cited by 11 other
academic articles since its recent publication date. The paper discusses the value
of the Clinical Global Impressions (CGI) Scale for a clinician to quantify and
monitor individual progress and treatment response over a period of time. The
CGI is a brief assessment of the patient’s history, psychosocial circumstances,
symptoms, behaviour, and the impact of the symptoms on the patient’s ability to
function. It is a well-established tool applicable to all psychiatric disorders that
can be easily used to quantify serial change during the course of clinical trials.
Specifically, the CGI-Improvement scale is used to rate changes from the baseline
of treatment. The clinician rates the patient on a seven-point scale: 1=very much
improved since the initiation of the treatment to 7=very much worse since the
initiation of the treatment. The CGI-I was a behavioural assessment used in
clinical trials of Lokitonin to measure its efficacy in reducing impulsive
aggression in IED patients. Using the CGI-I provides a recognizable and
universally known efficacy measure of Lokitonin treatment.
(43) Mayo Clinic. Intermittent explosive disorder treatments and drugs. [Online].
Available from: http://www.mayoclinic.com/health/intermittent-explosivedisorder/DS00730/DSECTION=treatments%2Dand%2Ddrugs
[Accessed 25th March 2012].
The Mayo Clinic, in Rochester, Minnesota, is part of one of the largest
medical service centers in the world, which seeks to foster effective diagnosis
and treatment in a multitude of medical conditions. This website is dedicated to
providing basic health information and educating the community on clinical
conditions. The website dedicated a page to Intermittent Explosive Disorder (the
model for our drug) and described the symptoms, diagnosis, and treatment for
this condition. It was helpful for us to see the current available treatment options
for IED in order to justify our presence and validate the merit of Lokitonin over
other options.
(44) Sanders-Bush E., Hazelwood L. (2011). Chapter 13. 5-Hydroxytryptamine
(Serotonin) and Dopamine. In L.L. Brunton, B.A. Chabner, B.C. Knollmann (Eds),
Goodman & Gilman's The Pharmacological Basis of Therapeutics, 12e. Available from:
http://www.accessmedicine.com/content.aspx?aID=16662324
[Date Accessed: April 4, 2012].
Chapter 13 discusses the multiple actions of serotonin and its interaction with
multiple 5-HT receptor subtypes within the body. It goes on to state that 5-HT2A
receptors are highly abundant and widely distributed throughout the
gastrointestinal tract. This gives us the appropriate information to suspect that
there may be possible side effects due to the interaction of Lokitonin with 5HT2A receptors in the gastrointestinal tract, specifically at the site of intestinal
smooth muscle lining. This chapter is a credible source as it was published in a
renowned neuropharmacological textbook called Goodman & Gilman’s: The
Pharmacological Basis of Therapeutics, 12th edition.
- 32 -
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
(45) Kessler R, Coccaro E, Fava M, Jaeger S, Jin R, Walters E. The prevalence and
correlates of DSM-IV intermittent explosive disorder in the National Comorbidity
Survey Replication. Archives of General Psychiatry. [Online] 2006; 63(6): 669-678.
Available from:
http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&Term
ToSearch=16754840&ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_R
esultsPanel.Pubmed_RVDocSum [Accessed 27th March 2012].
The National Comorbidity Survey Replication is a survey designed to study
the prevalence of mental disorders in the United States using various
qualitative measures. It involved conducting the Composite International
Diagnostic Interview (CIDI) that was developed for the World Mental
Health Survey Initiative. By using a highly controlled representative
sample group and an exhaustive interview schedule which aimed to cover all
aspects of mental health in the ninety-minute long interview, it could be
inferred that the diagnostic statistics derived from this study were relatively
accurate.
(46) Kringelbach ML, Rolls ET. The functional neuroanatomy of the human
orbitofrontal cortex: evidence from neuroimaging and neuropsychology. Progress in
Neurobiology. [Online]. 2004; 72(5): 341-372. Available from:
http://www.sciencedirect.com/science/article/pii/S0301008204000395 [Accessed
Date: 2 April 2012].
The following source was used for its image of the orbitofrontal cortex. The
source comes from the Department of Experimental Psychology at the University
of Oxford. It also has a large number of references, making it more likely that the
information that it presents is accurate.
- 33 -
Group
Name:
TEAM THOR
Student
Names:
Alexandra Annibale, Clarence Chan, Bonnie Cheung, Amanda
(Vincci) Chiu, Victoria Maich, Amita Mall, Laila Nasser, Navneet
Natt, Jessie Peng, Catherine Yang
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