Abstract

Background

Progesterone induces Fos expression

VCS effects on PR-IR neurons

Integration Via PRs

References

Discussion
Board

The ovarian steroid hormones, estradiol and progesterone, induce the expression of sexual receptivity in female rats. Subsequent mating stimulation then influences reproductive behavior, including lordosis and duration of sexual receptivity. As intraneuronal progestin receptors (PRs) have a central role in regulating sexual behaviors, mating stimulation could influence sexual receptivity via PRs. To test this idea, Fos immunocytochemistry was used to determine if neurons influenced by afferent input from the social environment, by neurotransmitters, or by hormone injection also contain PRs. Mating stimulation, like progesterone, induces Fos expression in a variety of neuroanatomical areas. A subset of the Fos-expressing neurons also contains PRs, suggesting the presence of a population of neurons in which mating stimulation may influence PRs. Likewise, a population of neurons was observed that expresses Fos in response to stimulation with a D1 agonist, and a subpopulation of these neurons contains PRs. The finding that injection of a progestin antagonist reduces VCS-induced Fos expression in some of these neurons supports the idea that some cellular responses to VCS are mediated by PRs. These Fos-PR colocalization studies enable us to study the cellular processes by which afferent input influences PR-containing neurons. It is in these neurons that response to afferent input and to progesterone may be integrated.

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Presentation Number SAblaustein0310
Keywords: progesterone, sex behavior, vaginocervical