Herland J S, Julian F J, Stephenson D G
Department of Anesthesia Research Laboratories, Brigham and Women's Hospital, Boston, Massachusetts 02115.
Am J Physiol. 1993 Jan;264(1 Pt 2):H224-32. doi: 10.1152/ajpheart.1993.264.1.H224.
The effects of halothane (1.9 mM, 9.4 mM), enflurane (3.3 mM, 16.5 mM), and isoflurane (1.6 mM, 8.1 mM) on maximal Ca(2+)-activated force and Ca2+ sensitivity were studied in rat myocardial preparations rendered permeable by various methods. In preparations permeabilized either by mild homogenization or by saponin (50 micrograms/ml, 30 min), further disruption of the sarcolemma with 2% Triton X-100 resulted in increased maximal force and Ca2+ sensitivity. When membranes were mechanically disrupted or saponized, each vapor agent caused the myocardium to be more sensitive to Ca2+. In these preparations, maximal force was decreased by halothane but was not affected by enflurane or isoflurane. With cellular membranes completely disrupted by Triton, the previously observed increase in Ca2+ sensitivity caused by enflurane was reduced, whereas that caused by halothane and isoflurane was abolished and maximal force was decreased by halothane and isoflurane but was not affected by enflurane. These results indicate that 1) components associated with the cellular membrane systems normally modulate force in mammalian myocardium, and 2) halothane, enflurane, and isoflurane have complex effects on these components. These results therefore can explain some of the differences in inotropic effects that these agents exert on mammalian myocardium.
在通过各种方法使其具有通透性的大鼠心肌制备物中，研究了氟烷（1.9 mM，9.4 mM）、恩氟烷（3.3 mM，16.5 mM）和异氟烷（1.6 mM，8.1 mM）对最大钙激活力和钙敏感性的影响。在通过轻度匀浆或皂苷（50微克/毫升，30分钟）通透的制备物中，用2% Triton X-100进一步破坏肌膜会导致最大力和钙敏感性增加。当膜被机械破坏或皂化时，每种挥发性麻醉剂都会使心肌对钙更敏感。在这些制备物中，氟烷会降低最大力，但恩氟烷或异氟烷则无此影响。在用Triton完全破坏细胞膜后，先前观察到的由恩氟烷引起的钙敏感性增加有所降低，而由氟烷和异氟烷引起的钙敏感性增加则被消除，并且氟烷和异氟烷会降低最大力，但恩氟烷无此影响。这些结果表明：1）与细胞膜系统相关的成分通常调节哺乳动物心肌的力；2）氟烷、恩氟烷和异氟烷对这些成分具有复杂的影响。因此，这些结果可以解释这些药物对哺乳动物心肌的变力作用的一些差异。
