Denervation deeply affects muscle structure and function, the alterations being different in slow and fast muscles. Because the effects of denervation on fast muscles are still controversial, and high-throughput studies on gene expression in denervated muscles are lacking, we studied gene expression during atrophy progression following denervation in mouse tibialis anterior (TA). The sciatic ne...

Denervation deeply affects muscle structure and function, the alterations being different in slow and fast muscles. Since the effects of denervation on fast muscles are still controversial and high throughput studies on gene expression in denervated muscles are lacking, we studied gene expression during atrophy progression following denervation in mouse tibialis anterior (TA). The sciatic nerve...

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...

There is strong evidence that pinnipeds maintain a lipid-based, aerobic metabolism during diving. However, the few fiber-typing studies performed on pinniped skeletal muscles are not consistent with an aerobic physiological profile. The objective of this study was to reexamine the fiber type distribution throughout the primary locomotory muscles of the harbor seal Phoca vitulina. Results from i...

In several pathological and experimental conditions, the passive membrane conductance of muscle fibers (G(m)) and their excitability are inversely related. Despite this capacity of G(m) to determine muscle excitability, its regulation in active muscle fibers is largely unexplored. In this issue, our previous study (Pedersen et al. 2009. J. Gen. Physiol. doi:10.1085/jgp.200910291) established a ...

Spread-wing postures of birds often have been studied with respect to the function of behavior, but ignored with regard to the mechanism by which the birds accomplish posture. The double-crested cormorant, Phalacrocorax auritus, was used as a model for this study of spread-wing posture. Those muscles capable of positioning and maintaining the wing in extension and protraction were assayed histo...

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...

Highly sensitive enzyme assays developed to differentiate skeletal muscle fibers allow the recognition of three main fiber types: slow-twitch oxidative (SO), fast-twitch oxidative glycolytic (FOG), and fast-twitch glycolytic (FG). Myosin, the predominant contractile protein in mammalian skeletal muscle, can be separated based on the electrophoretic mobility under nondissociating conditions into...