title: Blockade by naloxone of cocaine-induced hyperactivity, reverse tolerance and conditioned place preference in mice.
abstract: Cocaine-induced hyperactivity was inhibited by a single administration of naloxone (2 and 5 mg/kg, i.p.), an opioid receptor antagonist, and naloxone administered prior to and during the chronic injection of cocaine attenuated the development of both cocaine-induced reverse tolerance and conditioned place preference (CPP). Dopamine (DA) receptor supersensitivity which developed in cocaine-induced reverse tolerant or CPP mice, was also inhibited by naloxone. Furthermore, naloxone reduced an apomorphine-induced striatal dopaminergic action, climbing behavior. Therefore, the present studies suggest that cocaine-induced dopaminergic behaviors, such as hyperactivity, reverse tolerance and CPP, may be commonly produced via activation of an opioid receptor. The development of DA receptor supersensitivity may be a possible common mechanism of cocaine-induced reverse tolerance and CPP, since cocaine-induced changes in sensitivity to apomorphine, as well as apomorphine-induced climbing behavior in mice, were both inhibited by naloxone.
authors.affiliation: Department of Pharmacology, College of Pharmacy, Chungbuk National University, South Korea.
authors.forename: H S
authors.initials: HS
authors.lastname: Kim
authors.forename: W K
authors.initials: WK
authors.lastname: Park
authors.forename: C G
authors.initials: CG
authors.lastname: Jang
authors.forename: K W
authors.initials: KW
authors.lastname: Oh
authors.forename: J Y
authors.initials: JY
authors.lastname: Kong
authors.forename: S
authors.initials: S
authors.lastname: Oh
authors.forename: H M
authors.initials: HM
authors.lastname: Rheu
authors.forename: D H
authors.initials: DH
authors.lastname: Cho
authors.forename: S Y
authors.initials: SY
authors.lastname: Kang
mesh_terms: D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D003042:Cocaine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D003216:Conditioning, Operant / Q000187:drug effects*; D004298:Dopamine / Q000502:physiology; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D018765:Dopamine Uptake Inhibitors / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D004361:Drug Tolerance; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009043:Motor Activity / Q000187:drug effects*; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D009294:Narcotics / Q000494:pharmacology*; D013239:Stereotyped Behavior / Q000187:drug effects
chemical_list: D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D018765:Dopamine Uptake Inhibitors; D009292:Narcotic Antagonists; D009294:Narcotics; D009270:Naloxone; D003042:Cocaine; D001058:Apomorphine; D004298:Dopamine