针刺正常骼肌及力竭肌对胞浆自由钙离子浓度的影响机制

利用荧光指示剂Fura2测定离体青蛙半腱肌胞浆自由钙离子浓度（Ca2+]i），已发现肌肉经长时间电刺激至力竭后，Ca2+]i上升。对针刺影响力竭肌Ca2+]i的机制进行了进一步探讨。研究发现，针刺正常肌使Ca2+]i上升，其上升可被钙通道阻滞剂异博定大部分阻断；针刺电刺激后半腱肌则使Ca2+]i下降，其下降可被Na－Ca交换阻断剂奎尼丁阻断。如在针刺前予先加入奎尼丁，可抑制针刺对电刺激肌的降钙作用。上述结果证实：1）针刺正常肌的升钙作用主要由于细胞膜慢钙通道开放：2）针刺电刺激肌的降钙作用则是通过提高细胞膜对Na+通透性，促进Na－Ca交换而完成。研究亦发现，在针刺入肌肉的留针期内，细胞内Ca2+有上升和下降两类反应。其意义与机制尚待探讨。

Mechanism of the Effect of Acupuncture on Cytosolic Ca~(2+) Concentration in Normal and Exhausted Muscles

Using fluorescence indicator Fura 2 to measure cytopeasmic Ca2+ concentration (Ca2+]i), we studied the mechanism of the effect of acupuncture on Ca2+]i in frog isolated semitendinosus muscles. Results showed that acupuncture needling caused a rise in Ca2+]i of normal muscle,which may be blocked by verapamil, a slow calcium channel inhibitor. In electrically stimulated muscle, acupuncture needling caused a decrease in Ca2+]i. However,the needling effect may be inhibited by quinidine,a Na-Ca exchange blocker,or be blocked if the drug was added before needling,The findings demonstrated that: 1)the needling effect of increasing Ca2+]i in normal muscles was mainly due to opening a slow calcium channel in sarcolemmal;2) the needling effect of decreasing Ca2+]i in stimulated muscles was finished by increasing membrane permeability to sodium and then facilitating Na-Ca exchange. We also found that during insertion of the needle into normal and stimulated muscles, Ca2+]i showed two kinds of rection of rise and fall,the significance and mechanism of which demand further studies.