OXYTOCIN IMMUNOREACTIVITY IN THE HYPOTHALAMUS OF FEMALE HAMSTERS

In Syrian hamsters (Mesocricetus auratus), oxytocin (OXT) activity wit hin the medial preoptic-anterior hypothalamus (MPOA-AH) and the ventro medial hypothalamus (VMH) plays an important role in the expression of sexual receptivity. Immunocytochemical analysis with OXT-specific ant ibodies was used to identify the distribution of OXT-containing cell b odies and fibers in female hamster brain and to determine the possible sources of OXT important for sexual receptivity. Oxytocin-immunoreact ive cell bodies and fibers were found in several regions of the preopt ic area, including the medial preoptic area, the medial preoptic nucle us, and the bed nucleus of the stria terminalis. Large numbers of cell bodies and fibers were localized within the paraventricular and supra optic nuclei, and in anterior hypothalamus. OXT-immunoreactive fibers were observed in the VMH and the ventral tegmental area. The anatomica l data from the present study support the hypothesis that OXT activity in the MPOA-AH and VMH plays an important role in the regulation of s exual receptivity in hamsters.