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Table 48-1a
Table 48-1b
Drugs can alter your mood or your emotional
state.
•  Excitatory drugs increase nerve impulse
transmission. Examples:
•  Nicotine
•  Cocaine
•  Amphetamines (Dexedrine, Ritalin,
Adderall)
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Drugs can alter your mood or your emotional
state.
•  Inhibitory drugs decrease nerve impulse
transmission. Examples:
•  Benzodiazepines
•  Alcohol
•  THC (tetrahydrocannabinol)
–  the main psychoactive drug in marijuana
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Drugs can change synaptic transmission in the
following ways:
•  -Block a receptor for a neurotransmitter
(drug has structure similar to neurotransmitter)
-Therapeutic drugs called beta blockers compete
with norepinephrine for receptor sites.
Can treat hypertension and heart disorders by
slowing heart rate and reducing force of
contraction.
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Drugs can change synaptic transmission in the
following ways:
•  -Block release of a neurostransmitter
•  -example- Tetanus and botulinum neurotoxins
block neurotransmitter release
•  *Botox is used to cause muscle relaxation to
decrease wrinkles and to help treat migraines!
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Drugs can change synaptic transmission in the
following ways:
•  -Enhance release of a neurotransmitter•  example- amphetamines pass directly into
neurons containing dopamine and norepinephrine;
•  -cause the vesicles in the synaptic terminals to
fuse with the membrane and release into the cleft.
-The high concentrations of dopamine cause
euphoria and high concentrations of
norepinephrine cause alertness and high energy
effects.
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Drugs can change synaptic transmission in the
following ways:
•  -Enhance neurotransmission by mimicking a
neurotransmitter
•  (when drugs have the same chemical structure as the
neurotransmitter they have the same effect but are not
broken down as easily so the effect is stronger because
they stay longer in the synapse)
•  example- nicotine mimics acetylcholine (Ach) - acts on synapses in the
brain to cause a calming effect
•  -enzyme that breaks down acetylcholine cannot break down nicotinenicotine causes the the postsynaptic cell to release dopamine ->
feeling of pleasure (reward pathway)
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Drugs can change synaptic transmission in the
following ways:
•  -another example- THC mimics the
neurotransmitter anandamide, causes the
postsynaptic neuron to become hyperpolarized ->
interferes with short term memory and causes
motor impairment
•  Sensations from THC vary from relaxed to a sense
of panic and paranoia.
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Drugs can change synaptic transmission in the
following ways:
•  -Block removal of a neurotransmitter from the
synapse and prolong the effect
•  example- cocaine blocks the removal of dopamine
from the synapse so that it builds up
•  this leads to overstimulation of the postsynaptic
neuron -> euphoria and alertness
http://science-education.nih.gov/
supplements/nih2/addiction/activities/
lesson3_cocaine.htm
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Drugs can change synaptic transmission in the
following ways:
•  -Increases the binding of the neurotransmitter
to the receptor
•  example- Benzodiazapine increases the binding
of GABA to the receptor and causes the
postsynaptic neuron to become hyperpolarized.
This can reduce anxiety and be used against
epileptic seizures
•  example- Alcohol acts similar to Benzodiazapine
-> sedative effect. Alcohol also helps to increase
the release of dopamine.
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http://outreach.mcb.harvard.edu/animations/
synapse.swf
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Causes of Addiction:
•  -The body develops a tolerance and needs more
and more of the drug to produce the same result.
•  Addiction is a chemical dependency on drugs
where the drug has “rewired” the brain and has
become an essential biochemical in the body.
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Causes of Addiction
•  -Genetic predisposition (studies of twins)
–  Due to polygenic inheritance
•  - Social Factors (mental health of family or child,
peer pressures, family addictions)
•  -Dopamine secretion- In drug addiction dopamine
receptors are constantly stimulated.
•  Overstimulation decreases the number of receptors and
the remaining receptors become less sensitive. This is
called desensitization or tolerance. More and more of the
drug is needed just to have a sense of well-being.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Medulla oblongata – controls automatic and
homeostatic activities, such as swallowing,
digestion and vomiting, breathing and heart
activity
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Cerebellum- coordinates unconscious functions,
such as movement and balance
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Hypothalamus- maintains homeostasis,
coordinating the nervous and endocrine
systems, secreting hormones
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Pituitary gland- the posterior lobe stores and
releases hormones produced by the
hypothalamus and the anterior lobe produces
and secretes hormones
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Cerebral hemispheres- act as the integrating
center for complex functions such as learning,
memory and emotions
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Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings