Shibata T, Blanck T J, Sagawa K, Hunter W
Department of Anesthesiology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Anesthesiology. 1989 Mar;70(3):496-502. doi: 10.1097/00000542-198903000-00021.
The authors examined the effect of halothane, enflurane, and isoflurane on the dynamic stiffness of rabbit papillary muscles in Ba2+ contracture. Ca2+ was replaced by Ba2+ in order to constantly activate myofibrils. The dynamic stiffness of the contractured muscle was examined by exposing the muscle to sinusoidal length perturbations at frequencies of 0.05-30 Hz under two concentrations of anesthetic, approximately 0.5, and 1.5-2 mM, and at two Ba2+ concentrations, 0.5 and 1.5-2 mM. The anesthetics had no effect on the frequency (fmin) at which minimum stiffness occurred, but markedly decreased the stiffness modulus at high frequencies (Khi). The decrease in Khi was significant for all anesthetics at the P less than 0.05 level. Increasing the Ba2+ concentration from 0.5 to 1.5-2 mM in the presence of 0.5 mM of anesthetic resulted in a return of Khi to control levels. The authors conclude that halothane, enflurane, and isoflurane did not alter actin-myosin ATPase kinetics, because fmin was unchanged, but decreased the number of crossbridge interactions, because Khi was significantly decreased by all three anesthetics.
作者研究了氟烷、恩氟烷和异氟烷对Ba2+挛缩状态下兔乳头肌动态僵硬度的影响。用Ba2+替代Ca2+以持续激活肌原纤维。在两种麻醉剂浓度（约0.5和1.5 - 2 mM）以及两种Ba2+浓度（0.5和1.5 - 2 mM）下，通过使肌肉暴露于频率为0.05 - 30 Hz的正弦长度扰动来检测挛缩肌肉的动态僵硬度。麻醉剂对出现最小僵硬度的频率（fmin）没有影响，但在高频时（Khi）显著降低了僵硬度模量。在P小于0.05水平时，所有麻醉剂导致的Khi降低均具有显著性。在存在0.5 mM麻醉剂的情况下，将Ba2+浓度从0.5增加到1.5 - 2 mM会使Khi恢复到对照水平。作者得出结论，氟烷、恩氟烷和异氟烷并未改变肌动蛋白 - 肌球蛋白ATP酶动力学，因为fmin未变，但减少了横桥相互作用的数量，因为所有三种麻醉剂均使Khi显著降低。
