Cigarette smoking is recognised to be a major risk factor for disease, but once started, the habit is hard to quit. Nicotine is mainly responsible for dependence on tobacco and, historically, nicotine addiction has been one of the hardest to break. Now scientists at Scripps Florida have found that blocking the orexin A receptor in animal models abolishes the stimulatory effects of nicotine on brain reward circuitries and significantly reduces the desire for nicotine. In the study, the selective orexin A receptor antagonist, SB-334867, was found to decrease nicotine self-administration in rats and also reduced motivation to seek and obtain the drug.
If Orexin A is also involved in sustaining nicotine addiction in human smokers, blocking the orexin A receptor could be a potential target for developing new smoking cessation treatments. The Scripps group are hoping to discover new orexin A antagonists that would help smokers quit the habit. The study was published in the Nov 24 online Early Edition of the Proceedings of the National Academy of Sciences.
The orexin A receptor appears to be widely involved in regulating motivated behaviour and other studies have shown that SB-334867 also reduces alcohol-seeking behaviour in rats.