Calcium/calmodulin-dependent protein kinase II (CaMKII) is the main CaMK in skeletal muscle and its expression increases with endurance training. Because CaMKII has been implicated as a regulator of mitochondrial biogenesis and calcium handling, we investigated the effects of acute CaMKII overexpression in skeletal muscle in vivo. We overexpressed α/β-CaMKII in adult rat m. gastrocnemius (GM) a...

Individual muscle contributions to body segment mechanical energetics and the functional tasks of body support and forward propulsion in walking and running at the same speed were quantified using forward dynamical simulations to elucidate differences in muscle function between the two different gait modes. Simulations that emulated experimentally measured kinesiological data of young adults wa...

Glucocorticoids cause insulin resistance in skeletal muscle. The aims of the present study were to investigate the effects of contraction on glucose uptake, insulin signaling, and regulation of glycogen synthesis in skeletal muscles from rats treated with the glucocorticoid analog dexamethasone (1 mg x kg(-1) x day(-1) ip for 12 days). Insulin resistance in dexamethasone-treated rats was confir...

Matar, W., T. M. Nosek, D. Wong, and J.-M. Renaud. Pinacidil suppresses contractility and preserves energy but glibenclamide has no effect during muscle fatigue. Am. J. Physiol. Cell Physiol. 278: C404–C416, 2000.—The effects of 10 μM glibenclamide, an ATP-sensitive K1 (KATP) channel blocker, and 100 μM pinacidil, a channel opener, were studied to determine how the KATP channel affects mouse ex...

No studies have investigated the mitochondrial function in permeabilized muscle fiber from cats. The aim of this study was to investigate tissue-specific and substrate-specific characteristics of mitochondrial oxidative phosphorylation (OXPHOS) capacity in feline permeabilized oxidative muscle fibers. Biopsies of left ventricular cardiac muscle and soleus muscle, a type I-rich oxidative skeleta...

Thiobarbituric acid reactant substances (TBARs) content, and the activities of glucose-6-phosphate dehydrogenase (G6PDh), citrate synthase (CS), Cu/Zn- and Mn-superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPX) were measured in the lymphoid organs (thymus, spleen, and mesenteric lymph nodes (MLN)) and skeletal muscles (gastrocnemius and soleus) of adrenodemedullated (ADM) rat...

1. The parameters of presynaptic inhibition of the Ia spindle afferents from soleus muscle by vibration have been investigated. The inhibitory effects increase with the amplitude of vibration, but decrease when the vibration frequency is increased.2. The monosynaptic reflex threshold of twenty-one single soleus motor units activated in the H (Hoffmann) reflex by a single electrical stimulus to ...

Insulin binding and 2-deoxy-d-glucose uptake were compared in the soleus, plantaris, and extensor digitorum longus (EDL) muscles, in vitro, since the known biochemical profile of the soleus differs markedly from the other two. The present study showed that insulin binding increased in all three muscles with increasing concentrations of insulin in the range of 0.2-30 nM. However, the increase in...

Numerous studies have reported alterations in skeletal muscle properties and phenotypes in response to various stimuli such as exercise, unloading, and gene mutation. However, a shift in muscle fiber phenotype from fast twitch to slow twitch is not completely induced by stimuli. This limitation is hypothesized to result from the epigenetic differences between muscle types. The main purpose of t...

Duchenne muscular dystrophy (DMD) induces sarcolemmal mechanical instability and rupture, hyperactivity of intracellular calpains, and proteolytic breakdown of muscle structural proteins. Here we identify the two sarcomeric tropomodulin (Tmod) isoforms, Tmod1 and Tmod4, as novel proteolytic targets of m-calpain, with Tmod1 exhibiting ∼10-fold greater sensitivity to calpain-mediated cleavage tha...