臨牀消化器内科 Vol.15 No.4(3)


特集名 消化管機能と受容体 -- 臨床とのかかわり
題名 アセチルコリン受容体
発刊年月 2000年 04月
著者 谷 礼夫 国際医療福祉大学臨床医学研究センター
【 要旨 】 アセチルコリン受容体にはニコチン受容体とムスカリン受容体とがあること,本稿に関係があるのは後者(消化管を含めて副交感神経支配臓器および中枢神経・神経節に存在する)であり,分子量約5万の一本鎖の糖蛋白質で細胞膜を7回貫通する分子構造を有し,薬理学的にM1,M2,M3の三つのサブタイプに分けられ,消化管はM3に属すること,受容体反応はGTP蛋白をtransducerとすること,本受容体に作用する薬剤の消化管領域における臨床応用として,アゴニストは麻痺性イレウスや急性胃拡張に対する治療,食道アカラシアの診断に,アンタゴニストは胃腸の痙攣性の疼痛,消化性潰瘍,過敏性腸症候群の治療に使用されていることについて記述した.
Theme The Role of Receptors in Gastrointestinal Functions
Title Acetylcholine Receptors
Author Norio Tani Center for Research of Clinical Medicine, International University of Health and Welfare, International Hospital of Health and Welfare
[ Summary ] Acetylcholine receptors are divided into two types, nicotinic receptor and muscarinic receptor. The latter is covered in this manuscript since it exists in those organs under the control of the parasympathetic nerve. It also exists in the central nervous system and the ganglions. Its molecular structure is a single-chain shaped glycoprotein, with a molecular weight of about 50,000, passing through the cell-membrane 7 times. Its response is transmitted to the inside of the cell, using GTP proteins as transducers. It is classified into three subtypes ; M1, M2 and M3. M1 exists in the central nervous system and ganglions. M2 exists in the heart, and M3 exists in the organs, except for the heart, under the control of parasympathetic nerves. As for the clinical application of drugs acting on muscarinic receptors in the area of the alimentary tract, agonists are used as a therapy for paralytic ileus, or acute gastrectasia and as one of the diagnostic tests of achalasia. Antagonists are used as a therapy for abdominal pain, due to spasms of the alimentary tract, peptic ulcers and irritable bowel syndrome. In using these drugs it must be keep in mind that they act not only on the alimentary tract, but also on other organs under the control of the parasympathetic nerves.
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