Effects of enflurane on excitation-contraction coupling in frog skeletal muscle fibers.
Effects of enflurane on excitation-contraction coupling in frog skeletal muscle fibers.
复制标题
安氟醚对青蛙骨骼肌纤维兴奋-收缩耦合的影响。
DOI：
10.1007/bf00583934
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Sakai,T
中科院分区：
文献类型：
--
作者：
Kurihara,S;Konishi,M;Miyagishima,T;Sakai,T
研究了安氟醚对蛙骨骼肌纤维兴奋收缩偶联(EC)的影响。低浓度安氟醚(19.13+/-0.70 mg%)和高浓度安氟醚(108.52+/-4.52 mg%)对静息膜电位无明显影响，但高浓度安氟醚使动作电位峰值降低，50%波幅持续时间延长。在抽动反应中，安氟醚降低了钙敏光蛋白Aequorin测定的光信号的峰值反应，但低浓度的安氟醚不能降低峰值张力。高浓度的安氟醚对光信号和张力均有明显抑制作用。在破伤风期间，低浓度的安氟醚部分消除了光信号和张力。在高浓度时，这种抑制作用明显，动作电位仅在强直刺激的初期观察到。安氟醚增强了快速降温性肌挛缩的光信号增加。在甘油化肌纤维中，安氟醚在低钙时使PCA-张力关系左移，在高钙时抑制最大激活张力。在不取消动作电位的情况下，安氟醚对抽动反应中光信号的抑制作用表明，安氟醚可抑制蛙骨骼肌纤维的EC偶联(但可促进咖啡因引起的SR的直接钙释放)，并增加收缩元件的钙敏感性。
The effect of enflurane on the excitation-contraction (EC) coupling of frog skeletal muscle fiber was studied. Low (19.13+/-0.70 mg%) and high (108.52+/-4.52 mg%) concentrations of enflurane did not cause substantial changes of the resting membrane potential but a high concentration of enflurane reduced the peak of action potentials and prolonged the duration measured at 50% peak amplitude. During the twitch response, enflurane reduced the peak response of light signal measured with calcium-sensitive photoprotein, aequorin, but peak tension was not diminished by a low concentration of enflurane. A high concentration of enflurane remarkably inhibited both light signal and tension. During tetanus, a low concentration of enflurane partially abolished light signal and tension. At the high concentration, this inhibitory effect was pronounced and action potentials were only observed in the initial phase of tetanic stimulation. Enflurane enhanced the increase of light signal observed in rapid cooling contracture. In glycerinated muscle fiber, enflurane shifted the pCa-tension relation to the left in low calcium and suppressed maximally activated tension at high calcium concentration. Inhibitory effect of enflurane on light signal in twitch response without abolition of action potential suggests that enflurane might inhibit EC coupling in frog skeletal muscle fiber (but it enhances direct calcium release from SR induced by caffeine) and increase calcium sensitivity of contractile element.