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.
Original language | English |
---|---|
Pages (from-to) | 37-46 |
Number of pages | 10 |
Journal | Behavioural Brain Research |
Volume | 85 |
Issue number | 1 |
DOIs | |
State | Published - Apr 1997 |
Bibliographical note
Funding Information:This researchw as supportedin part by a grant (1996-1997f)r om the ResearchC enterf or New Drug DevelopmentC,o llege of PharmacyS, eoul National UniversityR, epublico f Korea.
Keywords
- apomorphine
- climbing behavior
- cocaine
- conditioned place preference
- dopamine receptor supersensitivity
- hyperactivity
- naloxone
- reverse tolerance