Hayes E S, Barrett T D, Burrill D E, Walker M J
Department of Pharmacology and Therapeutics, The University of British Columbia, Vancouver, Canada.
Life Sci. 1996;58(16):1375-85. doi: 10.1016/0024-3205(96)00104-x.
The effects of halothane and isoflurane on ventricular intracellular action potentials recorded in situ in pentobarbital anesthetized rats were studied. Halothane (0.5, 1 and 2 vol.%) and isoflurane (0.75, 1.5 and 3 vol.%) did not have identical effects on rat epicardial action potentials recorded by floating microelectrodes. However, over the concentration range tested, both anesthetics reduced blood pressure and heart rate to a similar extent. Isoflurane did not effect the maximum rate of rise of the action potential amplitude. However, 3 vol.% isoflurane reduced the resting membrane potential from -72+/-2 to -65+/-3 mV (mean+/-SEM, p<0.05) while the highest concentration of halothane had no effect. Halothane (2 vol.%) reduced action potential amplitude from 74+/-4 to 65+/-3 mV (p<0.05) and reduced the maximum rise rate of action potential from 175+/-21 to 133+/-8 V/s (p<0.05). Both isoflurane and halothane prolonged action potential duration at 10, 25 and 50% repolarization while only halothane significantly shortened action potential duration at 75% repolarization, Thus the effects of halothane and isoflurane on ventricular transmembrane action potentials were similar, but not identical. The relevance of such observations to the antiarrhythmic actions of halothane, but not isoflurane in this species is not clear.
研究了氟烷和异氟烷对戊巴比妥麻醉大鼠原位记录的心室细胞内动作电位的影响。氟烷（0.5%、1%和2%体积分数）和异氟烷（0.75%、1.5%和3%体积分数）对漂浮微电极记录的大鼠心外膜动作电位的影响并不相同。然而，在所测试的浓度范围内，两种麻醉剂均使血压和心率降低到相似程度。异氟烷对动作电位幅度的最大上升速率没有影响。然而，3%体积分数的异氟烷使静息膜电位从-72±2 mV降低到-65±3 mV（平均值±标准误，p<0.05），而氟烷的最高浓度则没有影响。2%体积分数的氟烷使动作电位幅度从74±4 mV降低到65±3 mV（p<0.05），并使动作电位的最大上升速率从175±21 V/s降低到133±8 V/s（p<0.05）。异氟烷和氟烷均使动作电位在复极化10%、25%和50%时的持续时间延长，而只有氟烷在复极化75%时显著缩短动作电位持续时间。因此，氟烷和异氟烷对心室跨膜动作电位的影响相似，但并不相同。这些观察结果与该物种中氟烷而非异氟烷的抗心律失常作用的相关性尚不清楚。
