Muscle fatigue in the frog semitendinosus: role of the high-energy phosphates and Pi.
Muscle fatigue in the frog semitendinosus: role of the high-energy phosphates and Pi.
复制标题
青蛙半腱肌疲劳：高能磷酸盐和 Pi 的作用。
DOI：
10.1152/ajpcell.1992.263.4.c803
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Fitts,RH
中科院分区：
文献类型：
--
作者：
Thompson,LV;Fitts,RH
本研究的目的是确定单个青蛙骨骼肌纤维中ATP、磷酸肌酸（PC）、Pi、乳酸和糖原的浓度，并评估它们在肌肉疲劳病因学中的作用。将青蛙半腱肌（ST）疲劳，在选定的恢复时间点快速冷冻，并冷冻干燥，并将单纤维解剖，称重，并测定ATP、PC、乳酸、Pi和糖原。疲劳方案将峰值强直力（Po）降低至初始的8.5%，而ATP和PC分别从45.18降至33.16和128.90降至28.76 mmol/kg干重。乳酸和磷分别从29.36增加到100.84和33.04增加到142.50 mmol/kg干重。ATP的小幅下降限制了跨桥部队的生产，这是值得怀疑的。虽然PC和Po的恢复之间的显着相关性被证明（r = 0.994），显示最快的力恢复率的时间段与PC的变化不大。一个显着的相关性被证明之间的总回收率和H2 PO 4-形式的Pi和Po。总之，本研究的结果与高能磷酸盐（ATP和PC）介导肌肉疲劳的假设不一致。Pi随刺激的大幅增加以及总Pi和Po的H2 PO 4形式的恢复之间的高度相关性支持Pi在骨骼肌疲劳的产生中的作用。
The purpose of this study was to determine the concentration of ATP, phosphocreatine (PC), Pi, lactate, and glycogen in single frog skeletal muscle fibers and assess their role in the etiology of muscle fatigue. The frog semitendinosus (ST) muscle was fatigued, quick frozen at selected time points of recovery, and freeze-dried, and single fibers were dissected, weighed, and assayed for ATP, PC, lactate, Pi, and glycogen. The fatigue protocol reduced peak tetanic force (Po) to 8.5% of initial, while ATP and PC decreased from 45.18 to 33.16 and 128.90 to 28.76 mmol/kg dry wt, respectively. Lactate and Pi increased from 29.36 to 100.84 and 33.04 to 142.50 mmol/kg dry wt, respectively. It is doubtful that the small decline in ATP limited cross-bridge force production. Although a significant correlation between the recovery of PC and Po was demonstrated (r = 0.994), the time period showing the fastest rate of force recovery coincided with little change in PC. A significant correlation was demonstrated between the recovery of both total and the H2PO4- form of Pi and Po. In conclusion, the results of this study are incompatible with the hypothesis that the high-energy phosphates (ATP and PC) mediate muscle fatigue. The large increase in Pi with stimulation and the high correlation between the recovery of both total and the H2PO4- form of Pi and Po support a role for Pi in the production of skeletal muscle fatigue.