等长运动
磷酸肌酸
骨骼肌
收缩(语法)
肌肉收缩
化学
内科学
心脏病学
医学
能量代谢
作者
Coy D. Fitch,Rekha Chevli,Jerrold S. Petrofsky,Stephen J. Kopp
出处
期刊:Life Sciences
[Elsevier]
日期:1978-09-01
卷期号:23 (12): 1285-1291
被引量:18
标识
DOI:10.1016/0024-3205(78)90507-6
摘要
Abstract To evaluate the need for phosphocreatine as an energy reservoir to sustain isometric contraction of skeletal muscle, rats were depleted of phosphocreatine by feeding β-GPA (β-guanidinopropionate) as 1% of the diet. In the place of phosphocreatine, β-GPAP (phosphorylated β-GPA) accumulated to concentrations of 20–25 μmoles/g wet weight of muscle. Although the maximum isometric tension produced by the soleus was always less than that produced by the plantaris muscle, the maximum for either muscle was not significantly affected by feeding β-GPA. The endurance of experimental soleus muscles was prolonged, however. These muscles held 70% of their maximum isometric tension for 106 ± 40 seconds (mean ± SD, n = 4) whereas the value for five control muscles was 43 ± 18 seconds. With fatiguing, isometric contractions of control plantaris and soleus muscles, phosphocreatine concentrations decreased by 68–70%; in experimental muscles, the β-GPA concentration decreased less than 12%. This difference in phosphagen consumption demonstrates that skeletal muscle can sustain fatiguing, isometric contractions without using large amounts of phosphocreatine or a substitute phosphagen as an energy reservoir. Phosphocreatine hydrolysis during muscle contraction normally may serve some other purpose.
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