Objective(s): Previous studies showed that skeletal muscle microcirculation was reduced in chronic heart failure. The aim of this study was to investigate the effects of endurance training on capillary and arteriolar density of fast and slow twitch muscles in rats with chronic heart failure. Materials and Methods: Four weeks after surgeries (left anterior descending (LAD) artery occlusion), chr...

A description of cellular energetics of muscular contraction is given in terms of the rates and extents of high-energy phosphate splitting during contractile activity, in terms of high-energy phosphate resynthesis by respiration and net anaerobic glycolysis, and in terms of the associated uptake and/or release of H+. These chemical changes have been studied quantitatively by rapid freeze-clampi...

We exploited a variety of mouse models to assess the roles of JP45-CASQ1 (CASQ, calsequestrin) and JP45-CASQ2 on calcium entry in slow twitch muscles. In flexor digitorum brevis (FDB) fibers isolated from JP45-CASQ1-CASQ2 triple KO mice, calcium transients induced by tetanic stimulation rely on calcium entry via La(3+)- and nifedipine-sensitive calcium channels. The comparison of excitation-cou...

Motor nerve terminals are known to be vulnerable to a wide range of pathological stimuli. To further characterize this vulnerability, we have developed a novel model system to examine the response of mouse motor nerve terminals in ex vivo nerve/muscle preparations to 2 h hypoxia followed by 2 h reperfusion. This insult induced a rapid loss of neurofilament and synaptic vesicle protein immunorea...

Muscovy ducks display marked sexual dimorphism. The aim of our study was to analyse the consequences of dimorphism on muscular growth and, particularly, on the myofibrillar typology of the Pectoralis major and Sartorius muscles. In the Pectoralis muscle, we only found two fibre types: red fast-twitch oxido-glycolytic fibres (about 90%) and white fast-twitch glycolytic fibres. In the Sartorius, ...

The jaw muscles of a turtle [Mauremys (Clemmys) japonica (MCJ)], have been analyzed for the histochemical characteristics of their fiber types. Six jaw muscles of the MCJ have been analyzed for histochemical characteristics of their fiber types. In this study, fiber types in two groups of muscles are classified; 1) fast twitch glycolytic (FG), fast twitch oxidative glycolytic (FOG), slow twitch...

Paralyzed skeletal muscle sometimes becomes faster and more fatigable after spinal cord injury (SCI) because of reduced activity. However, in some cases, pronounced muscle activity in the form of spasticity (hyperreflexia and hypertonus) occurs after long-term SCI. We hypothesized that this spastic activity may be associated with a reversal back to a slower, less fatigable muscle. In adult rats...

The effects of lyotropic (swelling) anions (Cl(-), Br(-), NO(3)(-) and I(-)) on contractile properties of fast-twitch extensor digitorum longus (EDL) and slow-twitch soleus (SOL) muscles were investigated in vitro at 20 degrees C and 35 degrees C. Isolated muscles bathed in anionic Tyrode solution were stimulated directly and isometric single twitches and fused tetanic contractions were recorde...

Our purpose was to determine if physiological characteristics of skeletal muscles of dogs and cats are related to their histochemical and biochemical characteristics. Maximum oxygen consumption (VO2max) and blood flow (Q) at VO2max were determined for in situ muscles of dogs and cats. Compared to cat muscles, dog muscles per unit mass had higher succinate oxidase activities, VO2max's, and Q's a...

Being born directly into the aquatic environment creates unique challenges for the breathing muscles of neonatal cetaceans. Not only must these muscles be active at the instant of birth to ventilate the lungs, but their activities must also be coordinated with those of the locomotor muscles such that breathing takes place only at the water's surface. At least one major locomotory muscle of bott...