<基礎的研究発生病理>高血圧ラットの小動脈の神経性収縮に対するamilorideの作用について

概要

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Amiloride, a Na-Ca, Na-H exchange inhibitor, induces marked hypotension in hypertensive animals more than in normotensive animals. The drug is known to exert a hypotensive action through decrease of vascular resistance and the resistance is controlled mainly by sympathetic nerve induced contraction of small arteries. We studied the effects of amiloride on nerve mediated membrane potential changes and contraction in mesenteric arteries from WKY and SHRSP. Amiloride induced marked hypotension in SHRSP. Amiloride did not alter the amplitude of the excitatory junctional potential which indicates that the drug had no effect on transmitter release in this preparation. Amiloride inhibited the nerve mediated contraction to a greater extent in preparations from SHRSP than in those from WKY. Prazosin had similar inhibitory action on the nerve mediated contraction in preparations from WKY and SHRSP. Noradrenaline contraction of the artery was inhibited by amiloride in a similar manner as prazosin. The noradrenaline concentration-response curve was shifted to the right by amiloride, which indicates an alpha-1 receptor blocking action. These results indicate that amiloride induced marked hypotension in hypertensive rats through its inhibitory action in nerve mediated contraction. Mechanisms other than alpha-1 blocking action may also contribute to explain its greater inhibitory action in hypertensive rats.
近畿大学の論文
1990-12-30