Hypothalamic but not cortical grafts induce recovery of sexual behavior and connectivity in medial preoptic area-lesioned rats.

We have previously shown that hypothalamic fetal brain grafts induced recovery of sexual behavior in medial preoptic area (MPOA)-lesioned male rats. In the present series of experiments, male rats with completely abolished sexual behavior by MPOA lesions received either hypothalamic or frontal cortical fetal grafts. The animals that received hypothalamic grafts showed a gradual recovery of sexual behavior. In contrast, those animals who received cortical grafts did not recover sexual behavior during the 15 weeks after the graft. In addition, to evaluate the connectivity of the grafted tissue with the host brain, a retrograde tracer, fluorogold, was injected in the dorsal tegmental area. Fluorogold-labeled cells were found in the hypothalamic, but not in the cortical grafts. These results suggest that specificity of the grafted tissue and connectivity between brain grafts and host tissue are necessary for the recovery of male sexual behavior in MPOA-lesioned rats.