The role of mu- and kappa-opioid receptors in cocaine-induced conditioned place preference.
Effects of buprenorphine, U-50,488H, naltrexone and lithium chloride on cocaine conditioned place preference were examined. Buprenorphine, a mixed opioid agonist-antagonist, blocked the cocaine-induced place preference. Furthermore, the kappa-receptor agonist U-50,488H and the mu-receptor antagonist naltrexone both antagonized the cocaine preference. U-50,488H or naltrexone alone induced a place aversion in a dose-dependent manner. However, the cocaine-induced conditioned place preference was not blocked by lithium chloride, although the latter induced a conditioned place aversion, indicating that the antagonism of cocaine-induced place preference by U-50,488H or naltrexone does not result from a functional antagonism. These results suggest that mu- and kappa-opioid receptors may be involved in cocaine-induced conditioned place preference.
Suzuki
T
T
Department of Applied Pharmacology, School of Pharmacy, Hoshi University, Tokyo, Japan.
Shiozaki
Y
Y
Masukawa
Y
Y
Misawa
M
M
Nagase
H
H
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000818:Animals; D002047:Buprenorphine / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D003042:Cocaine / Q000494:pharmacology*; D003213:Conditioning, Psychological / Q000187:drug effects*; D008094:Lithium / Q000494:pharmacology; D018021:Lithium Chloride; D008297:Male; D009271:Naltrexone / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D017473:Receptors, Opioid, kappa / Q000187:drug effects / Q000502:physiology*; D017450:Receptors, Opioid, mu / Q000187:drug effects / Q000502:physiology*
D002712:Chlorides; D011759:Pyrrolidines; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D002047:Buprenorphine; D009271:Naltrexone; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D008094:Lithium; D018021:Lithium Chloride; D003042:Cocaine