Effects of halothane on single atrial, ventricular, and Purkinje fibers.
Effects of halothane on single atrial, ventricular, and Purkinje fibers.
复制标题
氟烷对单个心房、心室和浦肯野纤维的影响。
作者：
O. Hauswirth
用细胞内微电极的方法研究了氟烷对窦房肌、室肌和浦肯野纤维的作用。兔心房纤维对高浓度(2%)氟烷不是很敏感。在1%氟烷作用下，绵羊浦肯野纤维表现出明显的超极化，动作电位时程从370毫秒缩短到233毫秒，超调量从30 mV减小到21 mV。随着浓度的增加，上升的速度没有显著变化。在2%氟烷存在下，静息电势与1%氟烷的静息电位没有显着差异。动作电位和不应期的持续时间进一步缩短，分别为165毫秒和109毫秒。上升速率现在显著降低到245伏/秒，超调进一步降低到17毫伏。1%氟烷可使传导时间延长约20%，2%氟烷可使传导时间增加一倍以上。绵羊心室肌纤维在2%氟烷作用下，静息电位无明显变化。动作电位时程由338毫秒缩短至231毫秒，有效不应期由295毫秒缩短至208毫秒，超调量由21 mV降至11 mV。可能的机制，这些变化和可能导致的心律失常进行了讨论。其他内容
The action of halothane on sinoatrial, ventricular, and Purkinje fibers was studied by means of intracellular microelectrodes. Rabbit atrial fibers were not very sensitive to even high (2%) concentrations of halothane. Sheep Purkinje fibers showed a significant hyperpolarization from 82 mv to 87 mv, a marked shortening of the duration of the action potential from 370 msec to 233 msec, and a diminution of the overshoot from 30 mv to 21 mv under the influence of 1% halothane. The rate of rise was not significantly changed with this concentration. In the presence of 2% halothane the resting potential did not differ significantly from the value obtained with 1% halothane. The duration of the action potential and of the refractory period were further diminished to 165 msec and to 109 msec, respectively. The rate of rise was now significantly reduced to 245 v/sec and the overshoot further decreased to 17 mv. Conduction time was increased by about 20% with 1% halothane and more than twofold with 2% halothane. Ventricular fibers of sheep did not show significant changes of the resting potential under the influence of 2% halothane. However, the duration of the action potential was markedly shortened from 338 msec to 231 msec, the effective refractory period was significantly reduced from 295 msec to 208 msec, and the overshoot decreased from 21 mv to 11 mv. Possible mechanisms underlying these changes and which may cause arrhythmias are discussed. ADDITIONAL