title: A limited role for ghrelin in heroin self-administration and food deprivation-induced reinstatement of heroin seeking in rats.
abstract: Food deprivation (FD) or restriction augments the locomotor activating and reinforcing effects of drugs of abuse. It has been proposed that these effects might be mediated by FD-induced increase in plasma levels of ghrelin, a 28-amino acid orexigenic peptide demonstrated to functionally interact with the mesolimbic dopaminergic system. However, a role for ghrelin has been demonstrated only with psychostimulant drugs and alcohol associated behaviors. We therefore examined the role of ghrelin in ongoing heroin self-administration and FD-induced reinstatement of extinguished heroin seeking. As expected, infusions of ghrelin [0.0, 1.5 and 3.0 µg/rat, intracerebroventricular (i.c.v.)] produced increases in breakpoints on a progressive ratio schedule of heroin reinforcement. In contrast, central administration of a ghrelin receptor antagonist, [D-Lys-3]-GHRP-6 (0.0, or 20.0 µg/rat, i.c.v.) had no effect on ongoing heroin self-administration under a fixed-ratio 1 schedule, or on FD-induced reinstatement of heroin seeking. These results suggest that signals mediated through ghrelin receptors play a limited role in FD-induced augmentation of heroin reinforcement and reinstatement of extinguished heroin seeking.
authors: Department of Psychology, Center for Studies in Behavioral Neurobiology, Group de Recherche en neurobiologie comportementale, Concordia University, Montreal, QC, Canada.
authors: Tia
authors: T
authors: Maric
authors: Firas
authors: F
authors: Sedki
authors: Benedicte
authors: B
authors: Ronfard
authors: Danielle
authors: D
authors: Chafetz
authors: Uri
authors: U
authors: Shalev
mesh_terms: D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects; D003463:Cues; D005108:Extinction, Psychological; D005508:Food Deprivation / Q000502:physiology*; D054439:Ghrelin / Q000502:physiology*; D003932:Heroin / Q000008:administration & dosage / Q000494:pharmacology*; D006556:Heroin Dependence / Q000523:psychology*; D006727:Hormone Antagonists / Q000494:pharmacology; D008297:Male; D009042:Motivation; D009294:Narcotics / Q000008:administration & dosage / Q000494:pharmacology*; D009842:Oligopeptides / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D012054:Reinforcement, Psychology
chemical_list: C520836:GHRP-6, Lys(3)-; D054439:Ghrelin; D006727:Hormone Antagonists; D009294:Narcotics; D009842:Oligopeptides; D003932:Heroin