Fukushi Y, Wakui M
Tohoku J Exp Med. 1985 Sep;147(1):33-41. doi: 10.1620/tjem.147.33.
Effects of methylmercuric chloride (MMC) on the contractile responses to nerve and drug stimulation in the guinea-pig taenia coli were examined. MMC (25-50 microM) severely reduced both responses to electrical and pharmacological (nicotine) stimulation of cholinergic nerves without affecting the responses to direct stimulation of muscles. MMC also suppressed markedly the response to acetylcholine (ACh), but did not change the maximum response to ACh. Dose-inhibition curve for MMC on the response to nerve stimulation was quite similar to that on the response to externally applied ACh. MMC only at a high concentration slightly reduced the response to histamine. MMC depolarized the membrane of the smooth muscle by about 8 mV with the sucrose-gap method. However, conditioning depolarization of the muscle strip by a 25 mM-K solution did not suppress the response to ACh. It was suggested that MMC-induced inhibition of the responses of the guinea-pig taenia coli to cholinergic nerve stimulation resulted from the inactivation of the muscarinic receptor of the smooth muscle.
研究了甲基汞氯化物（MMC）对豚鼠结肠带对神经和药物刺激的收缩反应的影响。MMC（25 - 50微摩尔）严重降低了对胆碱能神经的电刺激和药理（尼古丁）刺激的反应，而不影响对肌肉直接刺激的反应。MMC还显著抑制了对乙酰胆碱（ACh）的反应，但没有改变对ACh的最大反应。MMC对神经刺激反应的剂量抑制曲线与对外源性ACh反应的剂量抑制曲线非常相似。MMC仅在高浓度时略微降低了对组胺的反应。用蔗糖间隙法，MMC使平滑肌膜去极化约8毫伏。然而，用25毫摩尔钾溶液对肌条进行预处理去极化并没有抑制对ACh的反应。提示MMC诱导的豚鼠结肠带对胆碱能神经刺激反应的抑制是由于平滑肌毒蕈碱受体的失活所致。
