Differential effects of pimozide and SCH 23390 on acquisition of learning in mice.
Our main purpose was to clarify the differences between the effects of dopamine D-1 (SCH 23390) and D-2 (pimozide) antagonists on memory acquisition in a water-finding and a one-trial passive avoidance task with ddY mice. In the water-finding task, pimozide (0.1 and 0.2 mg/kg i.p.) enhanced the acquisition of latent learning of mice although it suppressed exploratory behavior. In contrast, SCH 23390 (0.1 mg/kg i.p.) attenuated the acquisition of latent learning and suppressed exploratory behavior. In the passive avoidance task, pimozide (0.1 and 0.2 mg/kg i.p.) enhanced the acquisition of the passive avoidance response of mice. SCH 23390 (0.05 and 0.1 mg/kg i.p.) failed to enhance the acquisition of the passive avoidance response. These results could suggest that a moderate block of D-2 receptors enhances memory acquisition but blocking D-1 receptors affects it in an opposite way.
Ichihara
K
K
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Meijo University, Nagoya, Japan.
Nabeshima
T
T
Kameyama
T
T
D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D001362:Avoidance Learning / Q000187:drug effects; D001552:Benzazepines / Q000494:pharmacology*; D005106:Exploratory Behavior / Q000187:drug effects; D007858:Learning / Q000187:drug effects*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D010868:Pimozide / Q000494:pharmacology*
D014150:Antipsychotic Agents; D001552:Benzazepines; D010868:Pimozide