Dihydroetorphine-induced place preference was mediated by dopamine D1 receptors in rats.
OBJECTIVE
To study the influence of dopamine (DA) receptor antagonists upon the rewarding property of dihydroetorphine (DHE).


METHODS
Conditioned place preference (CPP) paradigm was used to characterize the rewarding effect of DHE. DA receptor antagonists were injected administered subcutaneously or peritoneally and microinjected into nucleus accumbens (NAcc).


RESULTS
DHE (0.05, 0.5, and 5.0 micrograms.kg-1, s.c.) produced place preference (P < 0.01). Both the DA receptor antagonist haloperidol and the selective D1 receptor antagonist Sch-23390 attenuated the place preference produced by DHE (0.5 microgram.kg-1, s.c.). l-Sulpiride and spiperone, selective D2 receptor antagonists, had no such effects.


CONCLUSIONS
The D1 (but not D2) receptors in NAcc are crucial in the mediation of the rewarding effect of DHE.
Liu
Z H
ZH
National Institute on Drug Dependence, Beijing Medical University, China.
Zhang
K G
KG
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001552:Benzazepines / Q000494:pharmacology; D018491:Dopamine Agonists / Q000494:pharmacology; D005048:Etorphine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D017447:Receptors, Dopamine D1 / Q000502:physiology*; D017448:Receptors, Dopamine D2 / Q000502:physiology; D013134:Spiperone / Q000494:pharmacology; D013469:Sulpiride / Q000494:pharmacology
D001552:Benzazepines; D018491:Dopamine Agonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D005048:Etorphine; D013134:Spiperone; D013469:Sulpiride; D006220:Haloperidol; C034765:18,19-dihydroetorphine