Cellular localization of estrogen receptors on neurones in various regions of cultured rat CNS: coexistence with cholinergic and galanin receptors

Abstract

Autoradiographic studies have shown that many neurones in explant cultures of rat neocortex, hippocampus, preoptic area and spinal cord express binding sites for [3H]-estradiol which are distributed over the cell bodies and primary processes. By means of immunohistochemistry, it was observed that neurones were labelled by monoclonal antibodies against estrogen alpha-receptors and a polyclonal antibody against estrogen beta-receptors. Immunoreactivity was distributed over the soma and primary processes of the cells, the nuclei being more intensely stained. Double-immunostaining revealed a colocalization of estrogen alpha- and beta-receptors on approximately half of the neurones in cultures from neocortex and hippocampus whereas in cultures from preoptic area and spinal cord only few cells were double-stained. On many neurones, a coexistence of estrogen receptors and cholinergic muscarinic or nicotinic sites was found. Furthermore, combined autoradiographic and immunohistochemical studies have shown a colocalization of receptors for estrogen and the neuropeptide [125I]-galanin. The coexistence of estrogen and cholinergic sites as well as of estrogen and galanin receptors on the same neurones are discussed with respect to neurodegenerative events such as Alzheimer's disease.

Molecular Endocrinology and Physiology of the Aging Central Nervous System

“…A coexistence of ER␣, ER␤, and cholinergic, muscarinic, or nicotinic sites occurs in many neurons of the neocortex and hippocampus (387). Autoradiography and immunohistochemistry also illustrate colocalization of ER with receptors for the neuropeptide galanin (387).…”

“…Immunohistochemistry using selective antibodies against ER␣ and ER␤ reveal colocalization of ER␣ and ER␤ in approximately half of the neurons in cultures from neocortex and hippocampus (387). However, in the POA and spinal cord, relatively little double-staining is observed.…”

“…Autoradiography and immunohistochemistry also illustrate colocalization of ER with receptors for the neuropeptide galanin (387). The coexpression of estrogen, cholinergic, and galanin receptors on the neurons has important relevance to age-related neurodegeneration, particularly in postmenopausal women.…”

Morphological Effects of Estrogen on Cholinergic NeuronsIn VitroInvolves Activation of Extracellular Signal-Regulated Kinases

“…3 H]estradiol in females and only 20% in males (Hosli and Hosli, 1999). This difference could account perhaps for the sprouting response in female but not in male cultures, but it will require additional work to elucidate the role of ERs in cholinergic neurite outgrowth.…”

Hippocampal Synapses Depend on Hippocampal Estrogen Synthesis

“…This decrease could be blocked by an antiprogestin. Furthermore, progesterone downregulates ERs which are widely distributed in the hip- pocampus Hösli and Hösli, 1999;Gundlah et al, 2000;Hart et al, 2001;Shughrue and Merchenthaler, 2001;Wehrenberg et al, 2001;Rune et al, 2002). Along this line, treatment of ovariectomized rats with estradiol, which results in an increase in spines on apical dendrites of CA1 pyramidal cells (for review, see Segal and Murphy, 2001;McEwen, 2002), does not prove direct effects of exogenously applied estradiol on spine or synapse formation.…”