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用金黄色葡萄球菌α毒素（α－ｔｏｘｉｎ）或β溶血皂素（β－ｅｓｃｉｎ）处理平滑肌小肌条，可将细胞膜穿通许多小孔，使膜对某些离子及物质的屏障作用消失，但不影响受体－Ｇ蛋白－第二信使系统的耦联。根据ｃａ￣（２＋）ＥＧＴＡ的平衡结合常数Ｋ进行计算，将高浓度（１０ｍｍｏｌ／Ｌ）ＥＧＴＡ和具一定Ｃａ￣（２＋）浓度的溶液按一定比例混合，可获得所需Ｃａ￣（２＋）浓度的缓冲溶液。后者通过膜小孔进入细胞内可将胞浆游离Ｃａ￣（２＋）浓度“钳制”（ｃｌａｍｐ）在某一要求的水平上。在该模型上可方便地观察一些不依赖胞浆游离Ｇａ￣（２＋）浓度变化的细胞活动过程。该法最适宜于研究激动剂对平滑肌的钙增敏作用及其机制。如适当良，亦可用于心肌、骨骼肌及其它细胞，对研究细胞内信号传导、药物作用机理等方面，有独到的优点。
Treatment of smooth muscle strips with either alpha-toxin or beta-escin can penetrate the cell membrane through many small pores, leaving the membrane’s barrier to some ions and substances disappearing, Does not affect the receptor-G protein-second messenger system coupling. Calculated according to the equilibrium binding constant (K) of Ca 2+ (2+) EGTA, high concentrations (10 mmol / L) of EGTA and solutions with a certain concentration of Ca 2+ are mixed in a certain ratio to obtain the desired Ca 2+ concentration Buffer solution. The latter enters the cell through the membrane pores to “clamp” the cytosolic free Ca ~ (2+) concentration to a desired level. In this model, we can easily observe some cellular activities that do not depend on changes in cytoplasmic free Ga ~ (2+) concentration. The method is most suitable for studying the calcium sensitizing effect of agonist on smooth muscle and its mechanism. If appropriate, can also be used for myocardial, skeletal muscle and other cells, the study of intracellular signaling, drug mechanism of action, has unique advantages.