Marcil Mariannick, Karelis Antony D, Péronnet François, Gardiner Phillip F
Département de Kinésiologie, Université de Montréal, Succursale Centre-Ville, C.P. 6128 Montréal, Québec, H3C 3J7, Canada.
Eur J Appl Physiol. 2005 Mar;93(5-6):569-74. doi: 10.1007/s00421-004-1273-4. Epub 2004 Dec 14.
Carbohydrate administration increases endurance in man, and this could be associated with a reduction in muscle glycogen utilization in type I but not in type II fibres. Glucose infusion also attenuates fatigue in the rat plantaris muscle (94% type II fibres) stimulated indirectly in situ, but this is not associated with a glycogen sparing effect. The aims of this study were to verify if glucose infusion would attenuate fatigue and would reduce glycogen utilization in a muscle predominantly composed of type I fibres. For this purpose, the soleus muscle (84% type I fibres) was indirectly stimulated in situ in anaesthetized rats for 60 min while infusing either saline or glucose (1 g.kg(-1).h(-1); plasma glucose 7.7 mmol.l(-1) vs. approximately 5 mmol.l(-1) with saline only). The experimental data were expressed as the means (SD). With and without glucose, the dynamic force decreased by approximately 20% in the first minute of stimulation. With the infusion of saline, the dynamic force further decreased to 55% of the initial value at the end of the 60-min period of stimulation, but when glucose was infused for 60 min, the dynamic force remained constant at 78% of the initial value. When glucose was infused starting at min 30, dynamic force was partially restored. However, muscle glycogen utilization was not significantly different with the infusion of glucose compared to with the infusion of saline. These results suggest that glucose infusion attenuates fatigue in type I muscle fibres, but that this is not associated with any muscle glycogen sparing.
给予碳水化合物可增强人类的耐力，这可能与I型而非II型肌纤维中肌肉糖原利用率的降低有关。输注葡萄糖也可减轻大鼠原位间接刺激的比目鱼肌（94%为II型肌纤维）的疲劳，但这与糖原节省效应无关。本研究的目的是验证输注葡萄糖是否会减轻疲劳，并减少主要由I型纤维组成的肌肉中的糖原利用。为此，在麻醉大鼠中对其比目鱼肌（84%为I型纤维）进行原位间接刺激60分钟，同时输注生理盐水或葡萄糖（1 g·kg⁻¹·h⁻¹；血浆葡萄糖为7.7 mmol·L⁻¹，而仅输注生理盐水时约为5 mmol·L⁻¹）。实验数据以均值（标准差）表示。无论有无葡萄糖，在刺激的第一分钟动态力均下降约20%。输注生理盐水时，在60分钟刺激期结束时动态力进一步降至初始值的55%，但当输注葡萄糖60分钟时，动态力保持在初始值的78%不变。当从第30分钟开始输注葡萄糖时，动态力部分恢复。然而，与输注生理盐水相比，输注葡萄糖时肌肉糖原利用率并无显著差异。这些结果表明，输注葡萄糖可减轻I型肌纤维的疲劳，但这与任何肌肉糖原节省无关。
