Unloaded shortening velocity of skinned rat myocardium: effects of volatile anesthetics.
Unloaded shortening velocity of skinned rat myocardium: effects of volatile anesthetics.
复制标题
剥皮大鼠心肌的无负荷缩短速度：挥发性麻醉剂的影响。
DOI：
10.1152/ajpheart.1990.259.4.h1118
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Stephenson,DG
中科院分区：
文献类型：
--
作者：
Herland,JS;Julian,FJ;Stephenson,DG
采用松弛试验法测定了用50微克/毫升皂苷(50微克/毫升，30min)处理的大鼠脑室小梁的卸载缩短速度。该方法足够灵敏，可以检测到由3摄氏度的温度变化引起的空载缩短速度的17%可逆变化。在PCA 5.30(80%-90%激活)时，氟烷、安氟醚和异氟醚在剂量水平为8 mM或更大时使缩短速度减慢25%-30%，但在4 mM或更小时不会减慢缩短速度。在PCA 5.48(50%~60%激活)时，氟烷在4 mM或更大剂量水平使缩短速度减慢20-45%，但在2 mM时不减慢。麻醉药物对收缩速度的减慢作用在PCa为5.30时，氟烷、安氟醚和异氟醚的收缩速度在8 mm处达到饱和。当PCA为5.48时，氟烷在4 mm处达到饱和。这一结果表明，剂量-效应关系可能很窄，因此可以证明，PCA 5.48的剂量-反应关系在2-4 mM氟烷之间，而PCA 5.30的剂量-反应关系在4-8 mM氟烷之间。等长力和长度轴截距的麻醉剂量依赖关系与缩短速度的关系不一致。因此，在某些情况下，当缩短的速度减小时，力并没有显着减小。这可能被解释为麻醉药对相互作用的交叉桥的数量缺乏简单的抑制，并被解释为麻醉剂对交叉桥周期的直接影响。
The slack test method has been adapted for measurement of unloaded velocity of shortening in rat ventricular trabeculae that were skinned with saponin (50 micrograms/ml for 30 min). The method was sensitive enough to detect a 17% reversible change in the unloaded velocity of shortening produced by a 3 degrees C change in temperature. At pCa 5.30 (80-90% activation), halothane, enflurane, and isoflurane each slowed the shortening velocity by 25-30% at dose levels of 8 mM or greater but not at 4 mM or less. At pCa 5.48 (50-60% activation), halothane slowed the shortening velocity by 20-45% at dose levels of 4 mM or greater but not at 2 mM. The slowing effect of anesthetics on shortening velocity showed saturation at 8 mM for halothane, enflurane, and isoflurane when activation was at pCa 5.30. Saturation occurred at 4 mM for halothane when the pCa was 5.48. This result indicates that the dose-response relationship may be narrow, such that it can be demonstrated between 2 and 4 mM halothane for pCa 5.48 and between 4 and 8 mM halothane for pCa 5.30. The anesthetic dose dependence of isometric force and length axis intercept did not generally follow the same relationship as for the shortening velocity. Thus in several instances force did not significantly decrease when the velocity of shortening did. This may be interpreted as lack of simple inhibition by anesthetics on the number of interacting cross-bridges and as direct influence by anesthetics on the cross-bridge cycle.