Iaizzo P A, Lehmann-Horn F, Taylor S R, Gallant E M
Department of Pharmacology, Mayo Foundation, Rochester, MN 55905.
Muscle Nerve. 1989 Mar;12(3):178-83. doi: 10.1002/mus.880120303.
We studied the electrical properties of intact muscle fibers from normal and malignant hyperthermia-susceptible (MHS) pigs. Resting membrane potentials, action potentials, and current-voltage relationships were measured with and without the presence of halothane. There were no changes in the resting potentials or the specific membrane conductances at any concentration of halothane in either the normal or MHS fibers. The current-voltage relationships of normal and MHS fibers did not differ. Contractures were observed in MHS muscle when the concentration of halothane was greater than or equal to 0.8%. These halothane-induced contractures were not associated with depolarization of the surface membrane. Contractures were not observed in normal muscle even at concentrations of 6.0% halothane. In contrast, halothane altered the shape of the action potentials of both MHS and normal fibers. However, these changes were significantly greater in MHS fibers, occurred at much lower concentrations, and were partially prevented by preincubation in 10 microM dantrolene.
我们研究了正常猪和恶性高热易感（MHS）猪完整肌纤维的电特性。在有和没有氟烷存在的情况下，测量了静息膜电位、动作电位和电流-电压关系。在正常或MHS纤维中，任何浓度的氟烷都不会使静息电位或比膜电导发生变化。正常纤维和MHS纤维的电流-电压关系没有差异。当氟烷浓度大于或等于0.8%时，在MHS肌肉中观察到挛缩。这些氟烷诱导的挛缩与表面膜的去极化无关。即使在氟烷浓度为6.0%时，正常肌肉中也未观察到挛缩。相比之下，氟烷改变了MHS纤维和正常纤维的动作电位形状。然而，这些变化在MHS纤维中明显更大，发生在低得多的浓度下，并且通过在10微摩尔丹曲林中预孵育可部分预防。
