Orexin affects feeding, arousal, sleep, drug addiction

New research performed in rats suggests that orexin, a brain chemical involved in feeding behavior, arousal, and sleep, also plays a
role in reward function and drug-seeking behavior.

Dr. Glenda Harris and her colleagues at the University of Pennsylvania showed that the activation of orexin-secreting brain cells in
the hypothalamus, a brain region that controls many vital functions such as eating, body temperature, fat metabolism, etc. is
strongly correlated with food- and drug-seeking behaviors. Past anatomical studies have shown that these cells in the lateral
hypothalamus also project to adjacent reward-associated areas of the brain.

This study suggests that orexin may be a factor in modulating reward-seeking characteristic of substance abuse. The findings help
to better identify neural pathways involved in drug abuse, craving and relapse, which may ultimately help scientists find more
effective therapies.
http://www.drugabuse.gov/newsroom/05/NR8-25.html