Abstract
GABA acting via GABAA receptors exerts inhibitory actions on neurons. Certain endogenous steroids (neurosteroids) are modulators of GABAA receptors. Tetrahydroprogesterone (THP) and tetrahydrodeoxycorticosterone (THDOC) behave as allosteric agonists of the GABAA receptors, while pregnenolone sulfate (PS) and dehydroepiandrosterone sulfate (DHEAS) act as antagonists. The neurosteroids alter ligand binding, chloride transport and electrophysiological responses to GABA, acting at unique steroid recognition sites at the GABAA receptors. Certain behavioral effects of the neurosteroids are consistent with their GABA-agonistic or -antagonistic properties. For example, THP and THDOC manifest hypnotic and anxiolytic actions, while PS reduces barbiturate-induced sleep time. Physiologically changing levels of GABAergic steroids, during development, stress, phases of ovarian cycle or pregnancy may alter GABAA receptor function, thus influencing neuronal excitability and CNS arousal. For example, pregnancy and puerperium are associated with alterations of GABAA receptor function that seem attributable to steroid actions. GABA-ergic steroids also regulate uterine contractibility. This phenomenon may play a role in quieting the uterus during pregnancy and in its activation during parturition. (Review: Majewska, Prog.Neurobiol.38:379, 1992.)
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Majewska, M. GABAA RECEPTORS AND ACTIONS OF NEUROSTEROIDS. Pediatr Res 33 (Suppl 5), S9 (1993). https://doi.org/10.1203/00006450-199305001-00040
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DOI: https://doi.org/10.1203/00006450-199305001-00040