Isometric tetani of slow-twitch soleus and fast-twitch extensor digitorum longus (EDL) muscles of the mouse were studied at 20 degrees C. The total energy cost for 3- and 9-s isometric tetani was measured as a function of length above L0 and partitioned into a filament overlap-dependent fraction and a smaller filament overlap-independent fraction. In both muscles, the rate of filament overlap-i...

The primary purpose of this study was to determine the effect of prior exercise on insulin-stimulated glucose uptake with physiological insulin in isolated muscles of mice. Male C57BL/6 mice completed a 60-min treadmill exercise protocol or were sedentary. Paired epitrochlearis, soleus, and extensor digitorum longus (EDL) muscles were incubated with [3H]-2-deoxyglucose without or with insulin (...

Emerging evidence suggests that undercarboxylated osteocalcin (ucOC) improves muscle glucose uptake in rodents. However, whether ucOC can directly increase glucose uptake in both glycolytic and oxidative muscles and the possible mechanisms of action still need further exploration. We tested the hypothesis that ucOC per se stimulates muscle glucose uptake via extracellular signal-regulated kinas...

The ultimate goal of replantation and microsurgical reconstructive operations is to regain or improve impaired function of the tissue. However, the data related to the influence of NO on tissue function are limited. This study evaluated the effects of the NO donor S-nitroso- N-acetylcysteine (SNAC) on contractile function of skeletal muscle during reperfusion. Forty-nine rats were divided into ...

The aim of this study was to examine the effects of a prolonged high-intensity exercise, jumping, on procollagen alpha(1)(I) mRNA level and collagen concentration in different muscles of trained (T) and control (C) rabbits. Procollagen alpha(1)(I) mRNA expression was much higher (2.8 to 23.5 times) in semimembranosus proprius (SMP), a slow-twitch oxidative muscle, than in extensor digitorum lon...

We used intact fast-twitch extensor digitorum longus (EDL) and slow-twitch soleus muscles from rats and mice to test the hypothesis that exogenous application of an oxidant would increase maximum isometric force production (P(o)) of slow-twitch muscles to a greater extent than fast-twitch skeletal muscles. Exposure to an oxidant, hydrogen peroxide (H(2)O(2); 100 microM to 5 mM, 30 min), affecte...

The purpose of this study was to determine if PKB signaling is decreased and contractile protein degradation is increased in extensor digitorum longus (EDL) and soleus (SOL) muscles from middle-aged (MA) and aged (AG) mice. We also examined the effect of age on atrogene expression in quadriceps muscle. PKB activity, as assessed by Thr(308) and Ser(473) phosphorylation, was significantly higher ...

The purpose of this study was to investigate the potential role of creatine in GLUT4 gene expression in rat skeletal muscle. Female Wistar rats were fed normal rat chow (controls) or chow containing 2% creatine monohydrate ad libitum for 3 wk. GLUT4 protein levels of creatine-fed rats were significantly increased in extensor digitorum longus (EDL), triceps, and epitrochlearis muscles compared w...

Hypoxia as a consequence of acute and chronic respiratory disease has been associated with muscle atrophy. This study investigated the sensitivity of oxidative and glycolytic muscles to hypoxia-induced muscle atrophy. Male mice were exposed to 8% normobaric oxygen for up to 21 days. Oxidative soleus and glycolytic extensor digitorum longus (EDL) muscles were isolated, weighed, and assayed for e...

Grafting of 3-g extensor digitorum longus (EDL) muscles of cats may be made with (i) severence of the nerve with spontaneous reinnervation, termed standard grafts (ii) severence of the nerve with reinnervation facilitated by anastomosis of the nerve, termed nerve-anastomosed grafts; and (iii) preservation of the nerve, termed nerve-intact grafts. In previous studies, standard grafts developed a...