Pilegaard H, Asp S
Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, Denmark.
Am J Physiol. 1998 Mar;274(3):E554-9. doi: 10.1152/ajpendo.1998.274.3.E554.
The effect of prior eccentric contractions on skeletal muscle lactate/H+ transport was investigated in rats. Lactate transport was measured in sarcolemmal giant vesicles obtained from soleus and red (RG) and white gastrocnemii (WG) muscles 2 days after intense eccentric contractions (ECC) and from the corresponding contralateral control (CON) muscles. The physiochemical buffer capacity was determined in the three muscle types from both ECC and CON legs. Furthermore, the effect of prior eccentric contractions on release and muscle content of lactate and H+ during and after supramaximal stimulation was examined using the perfused rat hindlimb preparation. The lactate transport rate was lower (P < 0.05) in vesicles obtained from ECC-WG (29%) and ECC-RG (13%) than in vesicles from the CON muscles. The physiochemical buffer capacity was reduced (P < 0.05) in ECC-WG (13%) and ECC-RG (9%) compared with the corresponding CON muscles. There were only marginal effects on the soleus muscle. Muscle lactate concentrations and release of lactate during recovery from intense isometric contractions were lower (P < 0.05) in ECC than in CON hindlimbs, indicating decreased anaerobic glycogenolysis. In conclusion, the sarcolemmal lactate/H+ transport capacity and the physiochemical buffer capacity were reduced in prior eccentrically stimulated WG and RG in rats, suggesting that muscle pH regulation may be impaired after unaccustomed eccentric exercise. In addition, the data indicate that the glycogenolytic potential is decreased in muscles exposed to prior eccentric contractions.
在大鼠中研究了先前离心收缩对骨骼肌乳酸/H⁺转运的影响。在强烈离心收缩（ECC）2天后，从比目鱼肌、红色（RG）和白色腓肠肌（WG）获取肌膜巨囊泡，并从相应的对侧对照（CON）肌肉中测量乳酸转运。测定了ECC和CON腿的三种肌肉类型的物理化学缓冲能力。此外，使用灌注大鼠后肢制备方法，研究了先前离心收缩对最大刺激期间和之后乳酸和H⁺释放及肌肉含量的影响。从ECC-WG（29%）和ECC-RG（13%）获得的囊泡中的乳酸转运速率低于CON肌肉来源的囊泡（P<0.05）。与相应的CON肌肉相比，ECC-WG（13%）和ECC-RG（9%）的物理化学缓冲能力降低（P<0.05）。对比目鱼肌仅有轻微影响。ECC后肢在从强烈等长收缩恢复过程中的肌肉乳酸浓度和乳酸释放低于CON后肢（P<0.05），表明无氧糖原分解减少。总之，大鼠先前离心刺激的WG和RG中肌膜乳酸/H⁺转运能力和物理化学缓冲能力降低，提示不习惯的离心运动后肌肉pH调节可能受损。此外，数据表明暴露于先前离心收缩的肌肉中糖原分解潜力降低。
