Molecular Aspects of the Interaction between Estrogen and the Membrane Excitability of Hypothalamic Nerve Cells

Abstract

Publisher Summary This chapter describes the action of estrogen at the level of the nerve cell, utilizing the electrophysiological approach. Estrogen affects the electrical excitability of nerve cells that varies considerably in time of onset, ranging from a few milliseconds to several hours. Presumably, these time differences reflect the various ways in which estrogen can influence cell physiology, for example, from a direct action on the surface of the cell membrane resulting in an immediate change in the spontaneous firing rate to an alteration of the expression of the genome. The genomic action of estrogen on the nerve cell can be characterized by a slow onset of the estrogenic effect, which may take minutes, hours, or days following the penetration of the steroid into the cell; a duration of action, which may last for many hours; and sometimes even persistence of estrogenic action long after estrogen has disappeared. The nerve cell membrane poses no barrier to lipid-soluble estrogen. Thus, estrogen can initiate a membrane-mediated process that is associated with changes in ion permeability and subsequently interact with a specific cytoplasmic receptor for translocation into the cell nucleus. The latter is a critical step in hormone action while the physiological significance of the former remains to be defined.