Mating Induced Fos in Forebrain Neurons of Female Mice.

Abstract

Among researchers there is a widespread assumption that information about the sexual behavior of female rats and mice sex behavior may be interchangeable. During mating in both rats and mice, the male provides the female with tactile stimulation during mounts as well as vaginal-cervical stimulation (VCS) during intromissions and ejaculations. However, behavioral observations have revealed that female mice differ from rats in terms of the pattern of mating, the number of intromissions received, and even the hormonal requirements for mating to occur. Intromissive mating stimuli in rats induces significant increases in Fos-immunoreactivity (Fos-IR), a marker of neuronal activation, in several forebrain areas especially the medial amygdala (meAMY), and preoptic area (POA). However, it has not yet been demonstrated if the differences in sexual behavior observed between rats and mice may also indicate differences in the neuronal activity in the meAMY and POA of mice in response to different types of mating stimuli. This study aimed to characterize the neuronal activity in the meAMY and POA of female mice in response to different types of stimuli. Fos-IR was examined in hormone-primed ovariectomized female C57BL/6J mice after receiving either 15 intromissions or 15 mounts alone in comparison to females placed in an empty testing arena. It was found that in the meAMY, there was significantly more Fos-IR induced in the mounts alone group compared to the intromission and non-mated groups. In the POA, there was no significant difference of Fos-IR induction among the three groups.