Neurotransmitter orexin tied to pleasure

University of Pennsylvania School of Medicine researchers have discovered the neurotransmitter orexin influences reward-processing in the brain. By identifying the relationship between orexin neurons and behaviors associated with reward seeking, drug relapse and addiction, researchers hope to find new treatments for drug addiction.

Communication between the lateral hypothalamus and these brain regions suggests orexin neurons may have a role in motivation and reward-seeking behavior. Glenda Harris and Gary Aston-Jones examined orexin function in rats using a behavioral test aimed at mimicking food and drug reward-seeking and drug relapse. They found a strong association between the activation of orexin neurons in the lateral hypothalamus and reward-seeking of morphine, cocaine and food. “The lateral hypothalamus has been tied to reward and pleasure for decades, but the specific circuits and chemicals involved have been elusive,” said Aston-Jones.

“This is the first indication that the neuropeptide orexin is a critical element in reward-seeking and drug addiction,” he said. “These results provide a novel and specific target for developing new approaches to treat addiction, obesity and other disorders associated with dysfunctional reward processing.” The findings appeal online in Nature.

Science Daily
September 13, 2005

Original web page at Science Daily