Sensitization to the rewarding effects of morphine depends on dopamine.
The influence of dopamine (DA) on sensitization to the rewarding effects of morphine was evaluated. The effects of pre-treatment with saline or morphine plus naloxone, CGS 10746B, haloperidol, SCH 23390 and raclopride, on the place conditioning induced by 2 mg/kg morphine were evaluated. This dose was ineffective in saline pre-treated animals but induced a clear conditioned place preference in mice pre-treated with morphine, CGS 10746B or haloperidol. Conversely, animals pre-treated with morphine plus naloxone, CGS 10746B, SCH 23390, raclopride and the high dose of haloperidol did not acquire place preference. Our results demonstrated that DA release and subsequent DA D1 and D2 receptor activation is essential for the development of sensitization to the rewarding effects of morphine.
Manzanedo
Carmen
C
Departamento de Psicobiología, Facultad de Psicología, Universitat de València, Av. Blasco Ibañez, 21. 46010 Valencia, Spain.
Aguilar
María A
MA
Rodríguez-Arias
Marta
M
Miñarro
José
J
D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology; D004298:Dopamine / Q000378:metabolism*; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology; D011954:Receptors, Dopamine / Q000378:metabolism; D012201:Reward
D001552:Benzazepines; D011954:Receptors, Dopamine; D009270:Naloxone; D009020:Morphine; D004298:Dopamine