Prasad K
Recent Adv Stud Cardiac Struct Metab. 1975;10:119-37.
The effects of substrates on the metabolic inhibitor-induced changes in the action potential and contraction of papillary muscles obtained from patients undergoing corrective open-heart surgery were studied. Anoxia produced a marked shortening of the action potential duration and a decrease in the resting potential, rate of rise of action potential, effective refractory period, and contractility. In anoxic muscle, although glucose completely restored the action potential duration, effective refractory period, and resting potential to control levels, it was unable to completely restore the contractility to the control level. Substrate depletion and metabolic inhibitors (iodoacetate, dinitrophenol) produced effects similar to that of anoxia, but at a faster rate. Glucose restored the action potential and, to a lesser extent, contractility to the control level in dinitrophenol-treated muscle but was ineffective in so doing the iodoacetate-treated muscle. Pyruvate, however, was effective in restoring the action potential and contracility in iodoacetate-treated muscle. Pretreatment of the muscle with glucose and, particularly, with glucose plus insulin prevented the combined effects of anoxia and lack of glucose on the action potential and contractility for a prolonged period. These results suggest that intravenous infusion of glucose and insulin before and during surgery might prevent or reduced the effect of anoxia on the electrical and mechanical activity of the heart during open-heart surgery.
研究了底物对接受心脏直视矫正手术患者所取乳头肌动作电位和收缩的代谢抑制剂诱导变化的影响。缺氧导致动作电位持续时间显著缩短，静息电位、动作电位上升速率、有效不应期和收缩性降低。在缺氧肌肉中，尽管葡萄糖可使动作电位持续时间、有效不应期和静息电位完全恢复至对照水平，但无法使收缩性完全恢复至对照水平。底物耗竭和代谢抑制剂（碘乙酸盐、二硝基酚）产生的效应与缺氧相似，但速度更快。葡萄糖可使二硝基酚处理肌肉的动作电位恢复，收缩性在较小程度上恢复至对照水平，但对碘乙酸盐处理肌肉无效。然而，丙酮酸可有效恢复碘乙酸盐处理肌肉的动作电位和收缩性。用葡萄糖，尤其是葡萄糖加胰岛素预处理肌肉可长期防止缺氧和葡萄糖缺乏对动作电位和收缩性的联合效应。这些结果表明，手术前及手术期间静脉输注葡萄糖和胰岛素可能预防或减轻心脏直视手术期间缺氧对心脏电活动和机械活动的影响。
