Repeated administrations of (-)-deprenyl increase [3H]MK801 binding in rat brain and antagonize the impairment of passive avoidance conditioning induced by N-methyl-d-aspartate receptor antagonists

Repeated but not single administrations of the MAO type B inhibitor (-)-deprenyl (1 μmol/kg s.c. for 21 consecutive days) antagonized the impairment of passive avoidance retention induced by the N-methyl-d-aspartate (NMDA) receptor antagonists 2-amino-5-phosphonovalerate (APV), ketamine and dizocilpine (MK801), in rats. In well-washed membranes prepared from the hippocampi of rats repeatedly treated with (-)-deprenyl, the [3H]MK801 specific binding was increased. In contrast, repeated MAO B-selective doses of pargyline or (+)-amphetamine, as well as single injections with (-)-deprenyl failed to change [3H]MK801 binding. It is suggested that the effects of repeated (-)-deprenyl administrations upon NMDA receptors and upon the impairment of acquisition of a passive avoidance task induced by NMDA antagonists could be independent of MAO inhibition. © 1994.