Neuropeptide S Reinstates Cocaine-Seeking Behavior and Increases Locomotor Activity through Corticotropin-Releasing Factor Receptor 1 in Mice

Neuropeptide S (NPS) is a recently discovered neuropeptide that increases arousal and wakefulness while decreasing anxiety-like behavior. Here, we used a self-administration paradigm to demonstrate that intracerebroventricular infusion of NPS reinstates extinguished cocaine-seeking behavior in a dose-dependent manner in mice. The highest dose of NPS (0.45 nM) increased active lever pressing in the absence of cocaine to levels that were equivalent to those observed during self-administration. In addition, we examined the role of the corticotropin-releasing factor receptor 1 (CRF1) in this behavior as well as locomotor stimulation and anxiolysis. CRF1 knock-out mice did not respond to either the locomotor stimulant or cocaine reinstatement effects of NPS, but still responded to its anxiolytic effect. The CRF1 antagonist antalarmin also blocked the increase in active lever responding in the reinstatement model and the locomotor activating properties of NPS without affecting its anxiolytic actions. Our results suggest that NPS receptors may be an important target for drug abuse research and treatment and that CRF1 mediates the cocaine-seeking and locomotor stimulant effects of NPS, but not its effects on anxiety-like behavior.