Nicotine treatment regulates neuropeptide S system expression in the rat brain.

Nicotine has marked effects on sleep, arousal and body weight. However, the neuronal mechanisms underlying these actions are not fully understood. Neuropeptide S (NPS) is a recently discovered neuropeptide regulating sleep, anxiety and feeding. Here, we examined the effect of acute and chronic nicotine treatment on the expression of NPS and its receptor (NPS-R) in the hypothalamus and brainstem of rats by using real-time PCR. Our results showed that chronic nicotine treatment induced significant changes in NPS and NPS-R expression whereas acute treatment exclusively induces a marked increase in the mRNA levels of NPS-R in the brainstem. Interestingly, we detected no changes in the expression levels of other set of genes present both in hypothalamus and brainstem. Overall, these data suggest that NPS system is specifically regulated by nicotine in the rat hypothalamus and brainstem.