is a neuropeptide and neurons that respond to orexin found in the hypothalamus.
It helps in sleep wake cycle. There is an increased levels of dopamine and norepinephrine
in hypothalamus with the activation of these neurons and also there is an
increase in histamine levels. There are many studies which show that a defect
in orexin systems leads to narcolepsy disorder.
mechanism on which modafinil works is the increase in the amount of dopamine. It works with the blockage of the dopamine
transporters which are present in the brain as these are the molecules which
act in order to remove dopamine
from the synaptonemal complex. Thus modafinil increases the amount of dopamine and
also its availability for its action to work upon. Modafinil work like caffeine as it makes the
brain highly focused and also increases the levels of Dopamine D2 receptors.
Histamine is a chemical
which work as a neurotransmitter. It plays an important role in regulation of
sleep-wake cycle. Neurons of Histamine are found in the hypoathalamus in the
brain. Other than this these are present in tuberomammilary nuclei which are
also a part of hypothalamus. It elevates
the level of histamine.
vigilance and alertness. Besides this it accelerates the heart rate.
Norepinephrin is similar to
For balancing and
regulation of mood swings Serotonin plays an important role. Studies on
serotonin show that Modafinil is having the quality of improving the mood of
GABA (Gamma Amino
reduces the amount of gamma amino butyric acid which leads to increase in
histamine. GABA promotes sleep and also induces relaxation. So it also accounts
for the vigilance effects of Modafinil (Ferraro et al 1999).
Glutamate is the main
excitory neurotransmitter. It is involved in cognitive functioning (attention
and memory) of the brain. The levels of glutamate rise while using with
modafinil. (Ferraro et al 2005).