Effects of sexual behavioral manipulation on brain plasticity in adult rats

The purpose of the present study was to determine the effects of sexual beh aviorial manipulation on brain plasticity in adult male rats. Adult male Sp rague-Dawley rats that copulated during male sexual behavior testing were d ivided into four groups: control male; gonadectomized (Gdx) male; sexually active male; and sexually nonactive male. Female animals were used as an ad ditional control group. At the end of a 12-week experimental period, the an imals were again tested for male sexual behavior and tested for sexual moti vation. Sexual behavior manipulations over the 12-week period resulted in s ignificant differences in mount latency, mount frequency, intromission late ncy, intromission frequency, ejaculation latency, and the postejaculation i nterval. In the motivation test, significant differences in the number of a pproaches, contacts, and crossings of an electrified grid separating the te st animal from a receptive female were also observed. Sexually dimorphic nu cleus of the preoptic area (SDN-POA) Volumes in sexually nonactive males we re significantly smaller than in control males or sexually active males. An teroventral periventricular nucleus (AVPV) volumes in the male groups were not significantly altered by sexual behavioral manipulations, however, the nonactive AVPV vol. was the only vol, not significantly different from the control female vol. These data demonstrate that in the adult rat, sexual be havioral manipulations resulted in significant alterations in behavior and in the vol. of the SDN-POA and that the effect of sexual behavior on the AV PV needs to be further investigated. (C) 1998 Elsevier Science Inc.