[Compensating and reactivating effects of quinpirole on extinction of conditioned response and amnesia in mice with alternative behavioral stereotypes].

The effect of quinpirole on the passive avoidance habit retention in male C57BL/6J mice with aggressive and submissive behavioral strategies was studied during the habit extinction and amnesia. It was found that the activation of D2 dopamine postsynaptic receptors by quinpirole injections (1 mg/kg, i.p.) prolonged the passive avoidance retrieval during extinction in the submissive mice, while not affecting the basically high memory retrieval level in the aggressors. Under the amnesia conditions, quinpirole reactivated the passive avoidance retrieval irrespective of the base initial behavior status (aggressive versus submissive). It is concluded that the different basic state of the dopaminergic activity in mice predetermines the compensating-reactivating effect of quinpirole.