Nitric oxide synthases (NOS) convert L-arginine to nitric oxide in the presence of tetrahydrobiopterin (BH4). Two constitutive isoforms of NOS exist in normal skeletal muscle fibers, however, the existence of a third, the inducible isoform (iNOS), has never been detected in these fibers in vivo. Therefore, we assessed the influence of in vivo endotoxemia on skeletal muscle expression of constit...

Muscle atrophy is a serious and sometimes irreversExperiments were approved by the University Committee on Use and Care of Animals. ible consequence of peripheral nerve damage.4 Recently, we found that muscle atrophy is reversible to Four groups of denervated muscles were used in this study. In all groups, the soleus muscles were varying extents when denervated muscles are grafted with nerve im...

The influence of work-induced hypertrophy on the myosin of skeletal muscle was studied. Unilateral tenotomy of the gastrocnemius muscle (single tenotomy procedure) in normal rats led to rapid compensatory growth of the synergistic plantaris and soleus muscles. Total myosin increased with hypertrophy. The myosin from these hypertrophied muscles, however, was enzymatically and structurally identi...

The low-molecular-mass, cytosolic heart-type fatty acid-binding protein (H-FABP) is thought to be required for shuttling FA through the cytosol. Therefore, we examined the effects of an H-FABP-null mutation on FA and carbohydrate metabolism in isolated soleus muscle at rest and during a period of increased metabolic demand (30-min contraction). There were lower concentrations of creatine phosph...

The synthesis rates of different myosin isoenzymes in a single muscle, and of the same isoenzymes in different muscles (soleus, masseter and plantaris), were measured. The rate of total protein synthesis was significantly higher in the soleus [greater than 95% slow myosin (SM)] than in the plantaris [greater than 95% fast myosin (FM)]. Two fast isoenzymes, FM2 and FM3, were synthesized at diffe...

Duchenne muscular dystrophy (DMD) patients and the dystrophic mdx mouse have an elevated demand for ATP requiring processes, including Ca2+ regulation and skeletal muscle regeneration. As a key substrate for cellular ATP production, altered glycogen metabolism may contribute significantly to dystrophic pathology and explain reports of mild glucose intolerance. We compare the soleus and extensor...

Intracellular signaling exhibits circadian variation in the suprachiasmatic nucleus and liver. However, it is unclear whether circadian regulation also extends to intracellular signaling pathways in the cardiac and skeletal muscles. Here, we examined circadian variation in the intracellular mammalian target of rapamycin (mTOR)/70 kDa ribosomal protein S6 kinase 1 (p70S6K) and extracellular sign...

Denervation is known to induce skeletal muscle atrophy and fiber-type transitions, the molecular mechanisms of which are poorly understood. To investigate the effect of denervation on skeletal muscle, proteomic analysis was performed to compare denervated soleus muscle with normal soleus muscle. The muscles were fractionated to myofibrillar and sarcoplasmic fractions, which were analysed using ...

Soleus muscles in the rat were freely grafted alongside a normal Soleus muscle in the absence of mechanical trauma to any of the surrounding muscles or motor nerves . The object of this experiment was to determine whether or not the muscle grafts would become reinnervated under these circumstances . Contractile and histochemical properties of the grafts were compared with those of the contralat...

Proteasome inhibitors are novel potential drugs for therapy of many diseases, and their effects are not fully understood. We investigated direct effects of peptide vinylsulfone inhibitor AdaAhx3L3VS on protein and amino acids metabolism in rat skeletal muscle. Soleus and extensor digitorum longus muscles were incubated in a medium containing 30 micromol/l AdaAhx3L3VS or no inhibitors. Total pro...