INTERACTION BETWEEN THE NMDA COMPETITIVE ANTAGONIST CPP AND THE DOPAMINERGIC SYSTEM IN ONE-TRIAL INHIBITORY AVOIDANCE IN C57BL 6 MICE/

Post-training administration of the N-methyl-D-aspartate (NMDA) recept ors antagonist CPP, at doses of 0.5 and 1.0 mg/kg, impaired, in dose-d ependent fashion, retention of the inhibitory avoidance response in C5 7BL/6J (C57) mice. Post-training subeffective doses of selective D1 an d D2 dopamine receptor agonists, were able to antagonize the action of CPP, while subeffective doses of SCH 23390 and(-) sulpiride, respecti vely, D1- and D2-selective antagonists, enhanced the effects of the NM DA antagonist. Furthermore, subchronic blockade of dopamine receptor t hrough a 10-day daily treatment with 4 mg/kg of haloperidol induced an adaptation of both the dopaminergic and the glutamatergic system. The possible upregulation of D2 receptors, in response to repeated inject ion with haloperidol is shown in the one-trial inhibitory avoidance by an increased response to the D2 agonist. In addition, our data show a potentiation of CPP effects after the same treatment. These results s uggest a complex interaction between dopamine and glutamate in modulat ing one-trial inhibitory avoidance behavior in mice. (C) Academic Pres s, Inc.