Estrogen's sex-specific effects on ischemic cell death and estrogen receptor mRNA expression in rat cortical organotypic explants.

Estrogens, such as the biologically active 17-β estradiol (E2), regulate not only reproductive behaviors in adults, but also influence neurodevelopment and neuroprotection in both females and males. E2, contingent upon the timing and concentration of the therapy, is neuroprotective in female and male rodent models of stroke. studies suggest that E2 may partially mediate this neuroprotection, particularly in the cortex, via ERα.

Characteristic Response to Chemosensory Signals in GABAergic Cells of Medial Amygdala Is Not Driven by Main Olfactory Input.

Chemosensory stimuli from same species (conspecific) and different species (heterospecific) elicit categorically different immediate-early gene (IEG) response patterns in medial amygdala in male hamsters and mice. All heterospecific stimuli activate anterior medial amygdala (MeA) but only especially salient heterospecific stimuli, such as those from predators activate posterior medial amygdala (MeP). We previously reported that characteristic patterns of response in separate populations of cells in MeA and MeP distinguish between different conspecific stimuli.

GABAergic mechanisms contributing to categorical amygdala responses to chemosensory signals.

Chemosensory stimuli from conspecific and heterospecific animals, elicit categorically different immediate-early gene response-patterns in medial amygdala in male hamsters and mice. We previously showed that conspecific signals activate posterior (MeP) as well as anterior medial amygdala (MeA), and especially relevant heterospecific signals such as chemosensory stimuli from potential predators also activate MeP in mice. Other heterospecific chemosignals activate MeA, but not MeP.

Regulation of estrogen receptor alpha gene expression in the mouse prefrontal cortex during early postnatal development.

Estrogens have many functions in the developing rodent brain, and most of these depend on the presence of estrogen receptors. Understanding how expression of these receptors are regulated is crucial for understanding the roles of estradiol in the male and female brain during development In rodents, the prefrontal cortex (PFC) has been shown to be involved in working memory, attention, and behavioral inhibition. Many studies have demonstrated an effect of estradiol on sex difference in these functions attributed to differences in the PFC.

Epigenetic regulation of estrogen receptor beta expression in the rat cortex during aging.

During aging, there is an increase in neurodegenerative diseases and a decrease in cognitive performance. Postmenopausal women are more vulnerable as their estrogen levels decline, but most hormone replacement therapies do not prevent cognitive decline. One potential reason is that the timing of hormone replacement is critical and changes in the estrogen receptor expression may over-ride hormonal intervention.

Estrogen receptor-alpha gene expression in the cortex: sex differences during development and in adulthood.

17β-estradiol is a hormone with far-reaching organizational, activational and protective actions in both male and female brains. The organizational effects of early estrogen exposure are essential for long-lasting behavioral and cognitive functions. Estradiol mediates many of its effects through the intracellular receptors, estrogen receptor-alpha (ERα) and estrogen receptor-beta (ERβ).

Epigenetic regulation of estrogen receptor alpha gene expression in the mouse cortex during early postnatal development.

Estrogens play a critical role in brain development by acting on areas that express estrogen receptors. In the rodent cortex, estrogen receptor alpha (ER alpha) mRNA expression is high early in postnatal development but declines starting at postnatal day (PND) 10 and is virtually absent in the adult cortex. The mechanisms controlling this regulation are largely unknown.

Androgen resistance in squirrel monkeys (Saimiri spp.).

The goal of this study was to understand the basis for high androgen levels in squirrel monkeys (Saimiri spp.). Mass spectrometry was used to analyze serum testosterone, androstenedione, and dihydrotestosterone of male squirrel monkeys during the nonbreeding (n = 7) and breeding (n = 10) seasons.

Dynamic regulation of estrogen receptor-alpha gene expression in the brain: a role for promoter methylation?

Estrogen has long been known to play an important role in coordinating the neuroendocrine events that control sexual development, sexual behavior and reproduction. Estrogen actions in other, non-reproductive areas of the brain have also been described. It is now known that estrogen can also influence learning, memory, and emotion and has neurotrophic and neuroprotective properties.

Cortisol metabolism in the Bolivian squirrel monkey (Saimiri boliviensis boliviensis).

New World squirrel monkeys (Saimiri spp.) have high circulating cortisol levels but normal electrolytes and blood pressures. The goal of the present study was to gain insight into adaptive mechanisms used by Bolivian squirrel monkeys to minimize the effects of high cortisol on mineralocorticoid receptor (MR) activity and electrolyte and water balance.

Ovarian stimulation of squirrel monkeys (Saimiri boliviensis boliviensis) using pregnant mare serum gonadotropin.

The application of assisted reproductive technologies (ART) to nonhuman primates has created opportunities for improving reproductive management in breeding colonies, and for creation of new animal models by genetic modification. One impediment to the application of ART in Saimiri spp. has been the lack of an effective gonadotropin preparation for ovarian stimulation.

Distinctive responses in the medial amygdala to same-species and different-species pheromones.

Chemosignals related to reproductive and social status (pheromones) carry messages between opposite-sex and same-sex individuals in many species. Each individual must distinguish signals relevant to its own social behavior with conspecifics from signals used by other (heterospecific) species relevant to their social behavior. In male hamsters, the medial amygdala responded in a categorically different way to conspecific stimuli (socially relevant) and heterospecific stimuli (not socially relevant but serving similar purposes for other species), and may play an important role in this decision.

Pre-exposure to female chemosignals or intracerebral GnRH restores mating behavior in naive male hamsters with vomeronasal organ lesions.

Chemosensory input is essential for mating in male hamsters and the vomeronasal organ is critical to mating in naive males. In studies to investigate the convergence of vomeronasal chemosensory input and the neurohormone gonadotrophin releasing hormone (GnRH), we have unexpectedly found that pre-exposure to pheromone-containing chemosignals from female hamsters will also eliminate mating deficits normally seen in naive male hamsters with vomeronasal organs removed (VNX). In the present studies, naive-intact and naive-VNX male hamsters were given intracerebroventricular injections of GnRH or saline and exposed to female pheromones found in hamster vaginal fluid (HVF) or to water 40 min prior to a 5 min mating test.