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There are at least four known endothelin receptors, ETA, ETB1, ETB2 and ETC, all of which are G protein-coupled receptors whose activation result in elevation of intracellular-free calcium, which constricts the smooth muscles of the blood vessels, raising blood pressure, or relaxes the smooth muscles of the blood vessels, lowering blood pressure, among other functions. ==Physiological functions== *ETA is a subtype for vasoconstriction〔 These receptors are found in the smooth muscle tissue of blood vessels, and binding of endothelin to ETA increases vasoconstriction (contraction of the blood vessel walls) and the retention of sodium, leading to increased blood pressure. *ETB1 mediates vasodilation,〔 When endothelin binds to ETB1 receptors, this leads to the release of nitric oxide (also called endothelium-derived relaxing factor), natriuresis and diuresis (the production and elimination of urine) and mechanisms that lower blood pressure. *ETB2 mediates vasoconstriction〔 *ETC has yet no clearly defined function.〔 *ET receptor are also found in the nervous system where they may mediate neurotransmission and vascular functions. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Endothelin receptor」の詳細全文を読む スポンサード リンク
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