CHANGES IN GABA-BENZODIAZEPINE RECEPTOR COMPLEX AND IN PERIPHERAL BENZODIAZEPINE RECEPTORS IN MALE-MICE AFTER COPULATION

We studied the effect of copulation on GABA and benzodiazepine (BZD) r eceptors in the male mouse. After copulation, there was an 18% increas e in the in vitro number of [H-3]muscimol binding sites in frontal cor tex. No changes were observed in central BZD binding sites labelled ei ther in vivo by [H-3]flunitrazepam or in vitro (in olfactory bulbs and in frontal cortex) by [H-3]flumazenil, but further in vitro studies d emonstrated that the GABA-stimulated [H-3]flunitrazepam binding was re duced in both frontal cortex and olfactory bulbs. Copulation increased the number of peripheral BZD binding sites labelled by H-3-Ro 5-4864 in olfactory bulbs by 22% and in heart by 36%, but not in frontal cort ex or in testes. The changes of GABA/BZD and peripheral BZD receptors in mouse suggest that the GABAergic system may be affected by copulati on.