Slowing of relaxation in the fatiguing hamster diaphragm is enhanced by theophylline.
Slowing of relaxation in the fatiguing hamster diaphragm is enhanced by theophylline.
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茶碱可增强仓鼠隔膜的松弛速度。
DOI：
10.1152/jappl.1988.65.3.1307
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Esau,SA
中科院分区：
文献类型：
--
作者：
Esau,SA
用茶碱（100 mg/l）或咖啡因（100 mg/l）处理膈肌肌条，以研究在重复收缩和恢复期间对松弛时间常数（τ）的影响。使用两种刺激方案：高张力时间指数（TTI，60 Hz，160 ms，2/s）和低TTI（25 Hz，160 ms，1/s）。在高TTI方案中，在茶碱中注意到tau的早期增加，但在咖啡因或对照中没有。在低TTI方案中，tau与茶碱没有差异。还研究了茶碱（100 mg/l）和维拉帕米（5 μ M）的组合。维拉帕米可降低持续时间为300 ms的收缩力，但对持续时间为160 ms的收缩力无影响，对tau蛋白无影响。它不阻断用茶碱观察到的tau的延长。这些研究表明，茶碱对骨骼肌松弛有直接作用，维拉帕米不能阻止这种作用，而且外部钙对骨骼肌的持续收缩可能很重要。
Hamster diaphragm muscle strips were treated with theophylline (100 mg/l) or caffeine (100 mg/l) to study the effect on the time constant of relaxation (tau) during repeated contractions and with recovery. Two stimulation protocols were used: a high-tension time index (TTI, 60 Hz, 160 ms, 2/s) and a low TTI (25 Hz, 160 ms, 1/s). In the high TTI protocol an early increase in the tau was noted in theophylline but not in caffeine or control. In the low TTI protocol there was no difference in tau with theophylline. The combination of theophylline (100 mg/l) and verapamil (5 microM) was also studied. Verapamil decreased force in contractions of 300-ms duration but not in those lasting 160 ms and had no effect on tau. It did not block the prolongation of tau seen with theophylline. These studies suggest that theophylline has a direct effect on relaxation of skeletal muscle, which is not prevented by verapamil, and also that external calcium may be important for sustained contractions of skeletal muscle.