The dopamine antagonist, alpha-flupenthixol, interferes with naloxone-induced place aversion learning, but not with acute opiate dependence in rats

Pretreatment with the dopamine antagonist alpha-flupenthixol (alpha-flu) in terfered with the establishment of a naloxone-induced place aversion in two experiments. In Experiment 1, the potential of pretreatment with alpha-flu to interfere with the establishment of a naloxone-induced place aversion w as evaluated in rats administered morphine (Group MN) or saline (Group SN) 24 h prior to the naloxone conditioning trial. Naloxone-precipitated withdr awal from morphine administered :24 It prior to the trial produced a strong er place aversion than produced by naloxone alone. The neuroleptic, alpha-f lu, attenuated the naloxone-induced place aversion, but did not selectively interfere with the place aversion produced by acute opiate dependence. Exp eriment 2 replicated demonstration of interference with naloxone-place aver sion teaming by neuroleptic pretreatment with the inclusion of saline contr ols. These results suggest that dopamine modulates either the aversive moti vational properties of naloxone or teaming, even in opiate naive rats. (C) 2001 Elsevier Science Inc. All rights reserved.