Previous studies have implicated a part of the brain known as the lateral hypothalamus in reward and motivation. But the cells and neurotransmitters involved in these behaviours remained unknown. Now, a team led by Glenda Harris show that activation of neurons that contain the neurotransmitter orexin in this brain region is proportionally linked to food- and drug-seeking behaviours in rats.
The findings appear in an Advanced Online Publication from Nature. Orexin neurons have already been shown to have a role in sleep and arousal.
Harris and her colleagues have also demonstrated that blocking the orexin neurotransmitter itself abolishes the rats' addictive tendencies. Finally, they show that a relapse of drug-seeking behaviour can be induced by direct injection of this neurotransmitter into a major reward centre of the brain to which cells of the lateral hypothalamus project, known as the ventral tegmental area. The authors believe that the results suggest a potential new target for addiction treatments.
Glenda Harris (University of Pennsylvania, Philadelphia, PA, USA)
Abstract available online.
(C) Nature press release.
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