Dose-dependent cocaine place conditioning and D1 dopamine antagonist effects in male Japanese quail.

The dopamine D1 receptor subtype has been implicated in drug reward processes in mammals. Two experiments investigated whether dose-dependent differences in cocaine conditioned place preference (CPP) would be obtained in an avian species and whether these cocaine effects were mediated by the dopamine D1 antagonist R(+/-)-SCH23390. In Experiment 1, male birds were given intraperitoneal injections of 1, 3, 10, or 30 mg/kg of cocaine hydrochloride, paired with a chamber that contained distinct visual cues. On alternate days, they received saline paired with a chamber containing different visual cues. A CPP test was given after four pairings of cocaine with the distinct chamber. In Experiment 2, 0.0025, 0.025, or 0.25 mg/kg of SCH 23390 or saline was administered 15 min prior to cocaine (3 mg/kg) and placement into the least preferred chamber. CPP was observed at 1, 3, and 10 mg/kg doses of cocaine but not at 30 mg/kg or saline. All doses of SCH 23390 attenuated cocaine-induced CPP. The findings suggest that cocaine administration results in a dose-dependent CPP, and that similar with mammals, it may be mediated by D1 receptors in an avian species. Thus, the avian species may be a beneficial comparative model for drug studies, especially those involving visual cue mechanisms of drug reward.