Ohta T, Endo M, Nakano T, Morohoshi Y, Wanikawa K, Ohga A
Department of Pharmacology, Faculty of Medicine, University of Tokyo, Japan.
Am J Physiol. 1989 Feb;256(2 Pt 1):C358-67. doi: 10.1152/ajpcell.1989.256.2.C358.
To provide information regarding the cause of the muscle rigidity in malignant hyperthermia-susceptible (MHS) pigs, the Ca-induced Ca-release mechanism of the sarcoplasmic reticulum (SR), the Ca uptake by the SR, and the Ca-activated tension production of the contractile system were examined in skinned skeletal muscle fibers from MHS and normal pigs. In muscles of MHS pigs, the rate of Ca-induced Ca release was significantly higher than in normal muscle. The potentiation effect on Ca-induced Ca release by halothane and caffeine did not differ appreciably between MHS and normal fibers. The rate of Ca uptake by the SR and the Ca sensitivity of the contractile system of MHS fibers were not different from those of normal fibers, and halothane in an anesthetic concentration exerted no effect on them. Dantrolene inhibited the Ca-induced Ca release at 38 degrees C. These results suggest that the principal cause of malignant hyperthermia (MH) in MHS pigs is due to the enhancement of the Ca-induced Ca-release mechanism of the SR of the skeletal muscle.
为了提供有关恶性高热易感（MHS）猪肌肉僵硬原因的信息，在MHS猪和正常猪的去皮肤骨骼肌纤维中，研究了肌浆网（SR）的钙诱导钙释放机制、SR对钙的摄取以及收缩系统的钙激活张力产生。在MHS猪的肌肉中，钙诱导钙释放的速率显著高于正常肌肉。氟烷和咖啡因对钙诱导钙释放的增强作用在MHS纤维和正常纤维之间没有明显差异。MHS纤维的SR对钙的摄取速率和收缩系统的钙敏感性与正常纤维没有差异，麻醉浓度的氟烷对它们没有影响。丹曲林在38℃时抑制钙诱导的钙释放。这些结果表明，MHS猪恶性高热（MH）的主要原因是骨骼肌SR的钙诱导钙释放机制增强。
