Recently Discovered Neurotransmitter Involved in Pleasure, RewardAugust 26, 2005
Research Summary
Orexin (hypocretin), a neurotransmitter recently detected by researchers, is involved in the brain's pleasure and reward system and could play a role in addiction and treatment.Researchers at the University of Pennsylvania School of Medicine said that the findings about orexin -- previously linked to wakefulness and appetite -- could provide new avenues for addiction treatment research. Orexin seems to be involved in communication between the lateral hypothalamus region of the brain and the ventral tagmental area and nucleus accumbens.
"The lateral hypothalamus has been tied to reward and pleasure for decades, but the specific circuits and chemicals involved have been elusive," said Gary Aston-Jones, Ph.D., one of the study authors. "This is the first indication that the neuropeptide orexin is a critical element in reward-seeking and drug addiction. 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 association between orexin activation and reward seeking for morphine, cocaine, and food was found to be strong in animal studies, the researchers said. Scientists were able to initiate and curb craving by introducing and blocking orexin.
"These findings indicate a new set of neurons and associated neuronal receptors that are critical in consummatory reward processing," said Aston-Jones. "This provides a new target for developing drugs to treat disorders of reward processing such as drug and alcohol addiction, smoking, and obesity."
This research appears in the Aug. 14, 2005 issue of the journal Nature.
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