Belmar J, Ramírez B
Acta Physiol Lat Am. 1976;26(4):5-10.
Membrane potential and spike activity were recorded through intracellular electrodes from toad sartorius muscles superfused in Krebs solution. When this was replaced by a hypocalcic medium (1/20 of normal Krebs Ca2+ concentration), muscles showed extrajunctional sensitivity to acetylcholine, histamine and noradrenaline applied iontophoretically. Normal sensitivity was restored when muscles were bathed in normal calcium media. Changes in chemical excitability of the fibers immersed in hypocalcic solution were related to decreased input membrane resistance. These observations emphasize the role played by Ca2+ on electrical stability and chemical sensitivity of skeletal muscle membrane.
通过细胞内电极记录浸泡在克雷布斯溶液中的蟾蜍缝匠肌的膜电位和锋电位活动。当用低钙培养基（正常克雷布斯溶液Ca2+浓度的1/20）替换该溶液时，肌肉对离子电渗法施加的乙酰胆碱、组胺和去甲肾上腺素表现出接头外敏感性。当肌肉浸泡在正常钙培养基中时，恢复了正常敏感性。浸泡在低钙溶液中的纤维化学兴奋性的变化与输入膜电阻降低有关。这些观察结果强调了Ca2+对骨骼肌膜电稳定性和化学敏感性所起的作用。
