Download narcolepsy 2

NARCOLEPSY
A brief over view of the theory.
Hypocretin is a neurotransmitter that regulates arousal, wakefulness
and appetite.
In people who have narcolepsy this neurotransmitter is vastly reduced
in numbers because the cells that produce it have been destroyed by
the auto-immune response.
Some genetic variations on chromosome 6 predisposes an individual to
narcolepsy.
IDA- REDUCTIONIST
The theory of narcolepsy can be considered reductionist as sleep disorders
like narcolepsy have been explained using abnormalities of brain function for
example having a smaller amount of hypocretin neurotransmitters. Suggesting
that narcolepsy is caused solely by genetic variations and a lack of orexin
neurotransmitters means that the approach may neglect the influence that
psychological and sociocultural variables such as stress or a negative life
experience, could have. However the evidence found for biological factors
causing narcolepsy is very common and overwhelming and thus the fact that
this approach is reductionist may not be a negative thing. As the approach is
reductionist and only takes into account biological factors could mean that it
has useful applications for example in developing biological treatments for
Narcolepsy. It could also be that by isolating a single biological cause of a
disorder, more scientific research can be performed looking solely at that
cause. This could help to increase knowledge of the disorder and factors that
can cause it.
IDA- BIOLOGICALLY DETERMINIST
The theory of narcolepsy is biologically determinist to an extent as it
suggests that narcolepsy is caused solely by biological factors, for
example: a lack of the neurotransmitter oxerin in the brain and that
anyone with a genetic variation on chromosome 6 will predispose an
individual to developing narcolepsy and therefore not developing the
disorder is unavoidable if you have this genetic variation. The fact that
the theory is biologically determinist also suggests that individuals with
narcolepsy cannot reduce their symptoms by changing environment or
external factors, as the disorder is only influenced by biology. For
those suffering from narcolepsy this may mean they feel helpless and
like there is very little they can do to control or improve their condition.
However the approach is not completely biologically determinist as it
does suggest certain external factors, such as a flu vaccination, could
be responsible for triggering a biological response which in turn could
cause narcolepsy.
RESEARCH 1
Dement- carried out a study on mice who couldn’t make hypocretin.
This lead to the development of symptoms of narcolepsy. They also
had sleep attacks and cataplexy (symptoms of cataplexy are the jaw
dropping, the head slumping down, legs collapsing uncontrollably,
slurred speech) .
This supports the theory as it demonstrates the importance of
neurotransmitters in the occurrence of the sleep disorder. It also shows
low hypocretin decreases the ability to regulate arousal and
wakefulness.
Extra information- 10% of people with narcolepsy have cataplexy.
RESEARCH 2
Mellins
Research shows that people have low levels of a brain chemical called
hypocretin, which helps you stay awake. It is believed that this deficiency
is probably caused by an abnormal immune system attack on the brain
cells that produce hypocretin.
"Narcolepsy has been suspected of being an autoimmune disease," said
Dr. Elizabeth Mellins, a senior author of the study and an immunology
researcher at Stanford University School of Medicine, in California.
Supports idea that narcolepsy is due to the genetic variation on
chromosome 6 which causes low hypocretin levels , predisposing an
individual to narcolepsy
Also supports idea that maybe these people's immune systems are
attacking the neurones that are producing hypocretin, leading to the low
ability to regulate sleep
RESEARCH 3
Picchioni
63 narcoleptics and 63 controls
BACKGROUND:
This study sought to assess the risk of stressors and infectious diseases using a casecontrol study.
Method: A self-administered questionnaire was used to assess the frequency and timing
of possible risk factors.
RESULTS:
Of the infectious diseases examined, only flu infections and unexplained fevers carried
a significant risk. Several of the stressors carried a significant risk including a major
change in sleeping habits. When the timing of all risk factors was considered, exposure
prior to puberty increased the risk for developing narcolepsy.
CONCLUSIONS:
These findings emphasize the importance of environmental risk factors in the etiology of
narcolepsy. This highlights the need for further research on this aspect of narcolepsy so
RESEARCH 4
Siegal – UCLA
People with narcolepsy have nearly 65% more brain cells containing the
chemical histamine
Their research suggests that this excess of histamine cells may cause the loss of
hypocretin cells in human narcoleptics
This supports the idea that narcoleptics have fewer numbers of neurons in their
brain, such as hypocretin, meaning that this is the reason they cannot stay
awake as hypocretin is associated with wakefulness. Supports idea of their
body's immune system attacking neurones that produce hypocretin, or they may
a genetic variation on chromosome 6.
WIDER EVALUATION
This theory has practical applications because it offers great insight
into narcolepsy and has produced useful treatments such as drugs like
modafinil (which helps to improve wakefulness)
However, further research needs to be carried out to explore the
influence of the environment has in developing narcolpsy.
QUIZ
1. What neurotransmitter is linked to narcolepsy?
2. What is regulated by that neurotransmitter?
3. State one biological cause to narcolepsy.
4. What is the drug called that aids narcolepsy?
5. How many were in each group for Picchioni's study?
6.what animal was used in Dement's study?
7. Why is the theory of narcolepsy biologically determinist?
8. What are the symptoms of cataplexy?
9. What percent of people with narcolepsy have this?
10. What could be a positive thing about the approach being reductionist?
ANSWERS
1. hypocretin ( orexin )
2. arousal, wakefulness, and appetite
3. genetic variation in chromosome 6
4. Modafinil
5. 63
6.mice
7. because states narcolepsy is caused by solely genetic factors such as the genetic variation
in chromosome 6 and lack of neurotransmitter orexin.
8. the jaw dropping, the head slumping down, legs collapsing uncontrollably, slurred speech
9. 10%
10. can help develop biological treatments and allow more specific research