著者

杉本 治良 城戸 一哉 今村 一輝 蒲生 松助 西窪 靖和 村上 満彦

出版者

関西医科大学医学会

雑誌

関西医科大学雑誌 (ISSN:00228400)

巻号頁・発行日

vol.25, no.2, pp.179-187, 1973-06-20 (Released:2013-02-19)

参考文献数

11

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従来細胞膜の興奮はNaイオンの細胞への流入によつて始ると主張するナトリウム説で説明されてきたが,その後,外液のCaイオンが内向電流の担体であるとするカルシウム説を主張する一派があり,今日ではこれが一般に受け入れられているようである.しかしわたくしたちは,モルモット輸精管の摘出標本を等張蕉糖液申に置いた場合,少量の塩化カリウムによつて収縮が起ることを見出した.この現象は,外液中にCaイオンが全くなく,Naイオンも極めて少い状態で現われたので,この収縮過程にKイオンが主たる役割を果していると考えられた.また同時に行われた案験でCaイオンあるいはNaイオンはいかなる濃度においてもこの標本に収縮を来たすことがなく.またある一定濃度以上外液中に存在する場合には,かえつて上述のKイオンによる収縮を抑制することが見出された.このような実験的事実は,平滑筋収縮について従来用いられてきた概念では直ちに解釈できなかつたので,これに関連した実験もあわせて行い報告したい.

著者

城戸 一哉

出版者

関西医科大学医学会

雑誌

関西医科大学雑誌 (ISSN:00228400)

巻号頁・発行日

vol.25, no.1, pp.96-103, 1973-03-20 (Released:2013-02-19)

参考文献数

30

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Part I. Actions on the vas deferens preparation1) Trimetazidine gave scarcely any influence on the tension of the vas deferens preparation, when the drug was given to it independently.2) Noradrenaline induced the contraction of the preparation and this contraction was potentiated by the pre-addition of trimetazidine.3) When the tension of the preparat i on had been increased by the noradrenaline addition, the succeeding addition of trimetazidine could induce the contraction as if the more noradrenaline was added there.4) The vas deferens response to noradrenaline reduced in the calcium-free Locke's solution when the preparation had been kept in this medium for a fairly long time.5) In high calcium media, the potentiation of the noradrenaline contracti on by trimetazidine in the preparation was more remarkable than that seen in a Locke's solution, but the effect of trimetazidine was not so remarkable in low calcium media.6) In high or low potassium media, this kind of effect of trimetazidine was as much as that seen in a Locke's solution.7) In low sodium media, this effect of trimetazidine was much more remarkable than that seen in a Locke's solution, while it was scarcely seen in high sodium media. From these results, it was assumed that the potentiation of the noradren aline contraction by trimetazidine was caused by its action that can increase the available calcium ions released from the tissue, and that this action was manifested in low sodium or high calcium media while suppressed in high sodium media.Part II. The actions on the small intestine preparation1) Trimetazidine in high concentrations dec reased the smooth muscular tone and suppressed its spontaneous contractions.2) Trimetazidine in high concentrations suppressed the actions of barium chloride, nicotine, acetylcholine, serotonin, and histamine on the smooth muscle tone of the small intestine. From these results, it was assumed that trimetazidine has the anti-nicotinic action, and that the drug can suppressed the spontaneous contraction of the smooth muscle in the small intestine through its action suppressing the permeability of calcium or barium ions in the muscle membrane, in a different manner from that seen in the smooth muscle of the vas deferens.