Presence of calbindin and lack of parvalbumin in progesterone receptor-containing neurons of the monkey mediobasal hypothalamus.
All of the progesterone receptor-containing cells of the monkey hypothalamus are GABAergic. The aim of this study was to further characterize these GABAergic progesterone receptor-containing neurons based on their calbindin or parvalbumin content. These calcium-binding proteins are characteristic markers of different populations of GABAergic neurons in the central nervous system. Double-immunolabeling for progesterone receptor and either calbindin or parvalbumin was performed on hypothalamic Vibratome sections of estrogen primed African green monkeys (Cercopithecus aethiops). Progesterone receptor-containing calbindin-immunoreactive neurons were observed in the ventromedial and periventricular areas of the hypothalamus. Forty-one per cent of the progesterone receptor-containing cells in this area were calbindin immunopositive. No double-immunolabeled neurons could be detected in the infundibular (arcuate) nucleus. In tissue double-immunolabeled for progesterone receptor and parvalbumin, none of the progesterone receptor-containing neurons exhibited immunoreactivity for parvalbumin. Electron microscopic double-immunostaining for progesterone receptor and calbindin confirmed the light microscopic results. Furthermore, a large number of asymmetric synaptic contacts were observed on the calbindin-immunoreactive neurons. These observations demonstrate that progesterone receptor-containing cells in the monkey mediobasal hypothalamus consist of at least two different types of GABA neurons, and indicate that progesterone receptor-containing calbindin cells may be postsynaptic targets of excitatory fibers.
Horvath
T L
TL
Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, CT 06510.
Leranth
C
C
Naftolin
F
F
D000818:Animals; D064026:Calbindins; D002522:Chlorocebus aethiops; D005260:Female; D007033:Hypothalamus, Middle / Q000166:cytology* / Q000648:ultrastructure; D007124:Immunoenzyme Techniques; D016253:Microscopy, Immunoelectron; D009474:Neurons / Q000166:cytology* / Q000648:ultrastructure; D010320:Parvalbumins / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis*; D064030:S100 Calcium Binding Protein G / Q000032:analysis*
D064026:Calbindins; D010320:Parvalbumins; D011980:Receptors, Progesterone; D064030:S100 Calcium Binding Protein G