Theophylline does not increase maximal tetanic force or diaphragm endurance in vitro.
Theophylline does not increase maximal tetanic force or diaphragm endurance in vitro.
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茶碱在体外不会增加最大强直力或膈肌耐力。
DOI：
10.1152/jappl.1989.67.4.1655
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Miller,MJ
中科院分区：
文献类型：
--
作者：
Reid,MB;Miller,MJ
这些实验测试了茶碱提高膈肌力量（最大力量发展）和耐力（在反复收缩时维持力量输出）的能力。鼠膈条以最佳长度放置于含氧克雷布斯-林格溶液（37℃，pH 7.37）中。直接刺激采用最大电流密度、0.2 ms脉冲和250 ms强直性刺激。茶碱（500 mg/ml）在低刺激频率下增加了力的发展，但没有增加最大力[茶碱组25.7 +/- 0.5比对照组26.0 +/- 0.4 (SE) N/cm2 (N = 34)]。在重复的次极大（25 - 36hz）强直收缩中，茶碱不影响耐力。在重复的最大（160赫兹）强直收缩中，茶碱降低了耐力，加速了发达力量的下降。茶碱也抑制耐力试验结束后的力量恢复。我们认为茶碱不会增加体外膈肌的最大强直力，反而会降低体外膈肌的耐力。
These experiments tested the capacity of theophylline to improve diaphragm strength (maximal force development) and endurance (maintenance of force output during repeated contractions). Rodent diaphragm strips were mounted at optimal length in oxygenated Krebs-Ringer solution (37 degrees C, pH 7.37). Direct stimuli used supramaximal current density, 0.2-ms pulses, and 250-ms tetanic trains. Theophylline (500 mg/ml) increased force development at low stimulation frequencies but did not increase maximal force [25.7 +/- 0.5 for theophylline vs. 26.0 +/- 0.4 (SE) N/cm2 for control (n = 34)]. During repeated submaximal (25–36 Hz) tetanic contractions, theophylline did not affect endurance. During repeated maximal (160 Hz) tetanic contractions theophylline reduced endurance, accelerating the fall of developed force. Theophylline also inhibited recovery of force after endurance trials ended. We conclude that theophylline does not increase maximal tetanic force and can reduce diaphragm endurance in vitro.