Argov Z, Maris J, Damico L, Koruda M, Roth Z, Leigh J S, Chance B
Department of Biochemistry/Biophysics, University of Pennsylvania, Philadelphia 19104.
J Appl Physiol (1985). 1987 Oct;63(4):1428-33. doi: 10.1152/jappl.1987.63.4.1428.
Theoretical consideration and experimental findings of 31P nuclear magnetic resonance spectroscopy (NMR) studies of exercising human muscle suggest that a graded, steady-state work protocol is highly suitable for performance evaluation in health and disease. We describe a similar rat model for repeated 31P-NMR studies that follows many of the 31P-NMR features observed in normal human controls. Calf muscles of rats anesthetized with chloral hydrate were indirectly stimulated at four frequencies (0.25, 0.5, 1.0, and 2.0 Hz). It was found that 1) several steady states can be briefly maintained in this model; 2) work-induced phosphocreatine (PCr) fall and inorganic phosphate (Pi) rise is stoichiometric; 3) a linear relationship between stimulation rate and Pi/PCr was obtained, with a slope of 2.01 +/- 0.4 (+/- 2SD, n = 15); 4) no significant drop in ATP was observed, allowing the estimation of phosphorylation potential (PP) changes during this range of muscle work (PP at rest was 61,603 +/- 25,100 M-1 and fell to 6,700 +/- 900 M-1 at the end of exercise); and 5) poststimulation recovery was rapid, with a rate of 2.27 +/- 0.5 PCr/Pi U/min. This simple model can be used for prolonged studies of chronic animal muscle disorders.
对运动人体肌肉进行的31P核磁共振光谱（NMR）研究的理论思考和实验结果表明，分级稳态工作方案非常适合用于健康和疾病状态下的性能评估。我们描述了一种类似的大鼠模型，用于重复进行31P-NMR研究，该模型具有许多在正常人类对照组中观察到的31P-NMR特征。用氯水合氯麻醉的大鼠小腿肌肉以四种频率（0.25、0.5、1.0和2.0 Hz）进行间接刺激。结果发现：1）该模型可以短暂维持几种稳态；2）工作诱导的磷酸肌酸（PCr）下降和无机磷酸盐（Pi）上升是化学计量的；3）刺激率与Pi/PCr之间呈线性关系，斜率为2.01±0.4（±2SD，n = 15）；4）未观察到ATP有显著下降，从而可以在此范围内的肌肉工作期间估计磷酸化电位（PP）变化（静息时PP为61,603±25,100 M-1，运动结束时降至6,700±900 M-1）；5）刺激后恢复迅速，速率为2.27±0.5 PCr/Pi U/min。这个简单的模型可用于对慢性动物肌肉疾病的长期研究。
