title: Intraventricular administration of neuropeptide S has reward-like effects.
abstract: Neuropeptide S (NPS) is an endogenous brain peptide produced by neurons located in the lower brainstem, and functional studies suggest that NPS has arousing effects. Because its receptors are found in reward-associated regions throughout the brain, we evaluated whether intraventricular NPS injections elicit reward-related effects in rats. Rats increased lever presses that led to intraventricular administration of NPS (0.34-34 pmol per infusion) in a dose dependent manner, with a cue-assisted procedure. Cue-assisted self-administration of NPS was decreased by systemic administration of the dopamine receptor antagonist SCH 23390 (0.025 mg/kg, i.p.) or the hypocretin-1 (orexin-1) receptor antagonist SB 334867 (20 mg/kg, i.p.). In addition, intraventricular NPS injections (1000 pmol) induced conditioned place preference, whereas a lower dose (100 pmol) of NPS induced conditioned place aversion. Finally, NPS injections (100-1000 pmol) acutely facilitated locomotor activity, whereas repeated NPS injections did not lead to locomotor sensitization. Our data suggest that intraventricular NPS injections have reward-like effects in that NPS weakly facilitates seeking and induces positive reinforcement. These effects may depend on intact dopamine and hypocretin systems.
authors.affiliation: Behavioral Neuroscience Research Branch, National Institute on Drug Abuse, National Institutes of Health, US Department of Health and Human Services, Baltimore, MD 21224, USA.
authors.forename: Junran
authors.initials: J
authors.lastname: Cao
authors.forename: Luis
authors.initials: L
authors.lastname: de Lecea
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ikemoto
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D001552:Benzazepines / Q000494:pharmacology; D001583:Benzoxazoles / Q000494:pharmacology; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology; D018492:Dopamine Antagonists / Q000494:pharmacology; D007276:Injections, Intraventricular; D008124:Locomotion / Q000187:drug effects / Q000502:physiology; D008297:Male; D009287:Naphthyridines; D009479:Neuropeptides / Q000008:administration & dosage* / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011954:Receptors, Dopamine / Q000378:metabolism; D018013:Receptors, Neuropeptide / Q000037:antagonists & inhibitors; D012201:Reward; D012646:Self Administration; D014508:Urea / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: C420062:1-(2-methylbenzoxazol-6-yl)-3-(1,5)naphthyridin-4-yl urea; D001552:Benzazepines; D001583:Benzoxazoles; D018492:Dopamine Antagonists; D009287:Naphthyridines; D009479:Neuropeptides; D011954:Receptors, Dopamine; D018013:Receptors, Neuropeptide; C534628:SCH 23390; D014508:Urea