Estrogen receptor alpha containing neurons in the monkey forebrain: Lack of association with calcium binding proteins and choline acetyltransferase

The present study used single and dual immunohistochemistry to determine the topography and chemical phenotype of ERα containing neurons within the monkey forebrain utilizing antibodies directed against the full-length human ERα (NCL-ER-6F11), calcium-binding proteins calbindin-D_28k, and parvalbumin as well as choline acetyltransferase (ChAT). Our findings demonstrate for the first time ERα immunoreactive (-ir) cells in the monkey cerebral cortex (layers I-II) and in the claustrum. In addition, ERα-ir cells were seen in the septum, basal forebrain, amygdala and hypothalamus. Double-labeled cells for ERα and calbindin-D_28k were seen only in the ventrolateral part of the ventromedial hypothalamic nucleus. In contrast, the co-localization of ERα and parvalbumin or ChAT was not seen in any of the areas of the monkey forebrain examined. These observations suggest that estrogens, at least in part, via ERα regulate calbindin-D_28k hypothalamic but not parvalbumin or ChAT containing neurons in select monkey forebrain regions.