Baldwin K M, Roy R R, Sacks R D, Blanco C, Edgerton V R
J Appl Physiol Respir Environ Exerc Physiol. 1984 Jun;56(6):1602-7. doi: 10.1152/jappl.1984.56.6.1602.
Effects of spinal cord transection in 2-wk-old cats on the metabolic, histochemical, and fatigue properties of a fast- and a slow-twitch muscle were determined. Chronic (6-12 mo) spinalization (Sp) resulted in an increased ratio of fast-twitch, oxidative-glycolytic (FOG) to slow-twitch, oxidative (SO) fibers in soleus (SOL). In medial gastrocnemius (MG), Sp produced a histochemical profile suggesting that fast fibers were increased at the expense of slow fibers. Changes in biochemical markers for oxidative (citrate synthase) and glycolytic (GPD) potential were consistent with the histochemical findings. The fatigue index of Sp MG and SOL remained normal and was consistent with the type and degree of fiber type change. Daily treadmill exercise did not markedly alter any of the adaptations. The metabolic and fatigue properties of skeletal muscle of Sp cats are consistent with the view that as some fibers develop "faster-like" characteristics, the oxidative and the glycolytic potential is also enhanced. As was true of the contractile properties and related biochemical data, the changes observed suggest that significant changes occurred within as well as across fiber types. These data, in conjunction with that of chronic EMG recordings, provide evidence that there is a relative independence of both the oxidative potential and the fatigability of a muscle relative to its quantity of activation.
研究了脊髓横断对2周龄猫快速和慢速收缩肌肉的代谢、组织化学及疲劳特性的影响。慢性（6 - 12个月）脊髓横断（Sp）导致比目鱼肌（SOL）中快肌、氧化糖酵解型（FOG）与慢肌、氧化型（SO）纤维的比例增加。在内侧腓肠肌（MG）中，脊髓横断呈现出的组织化学特征表明快肌纤维增加而慢肌纤维减少。氧化（柠檬酸合酶）和糖酵解（甘油磷酸脱氢酶）潜能的生化标志物变化与组织化学结果一致。脊髓横断的MG和SOL的疲劳指数保持正常，且与纤维类型变化的类型和程度一致。每日跑步机运动并未显著改变任何适应性变化。脊髓横断猫骨骼肌的代谢和疲劳特性与以下观点一致：随着一些纤维呈现出“更快样”特征，氧化和糖酵解潜能也会增强。正如收缩特性和相关生化数据所示，观察到的变化表明纤维类型内部和之间都发生了显著变化。这些数据与慢性肌电图记录数据一起，提供了证据表明肌肉的氧化潜能和疲劳性相对于其激活量具有相对独立性。
