Mitsugumin 29 (MG29), a major protein component of the triad junction in skeletal muscle, has been identified to play roles in the formation of precise junctional membrane structures important for efficient signal conversion in excitation-contraction (E-C) coupling. We carried out several experiments to not only study the role of MG29 in normal muscle contraction but also to determine its role ...

This study was designed to determine if previously reported differences in the functional impairment of muscles composed of predominantly different fiber types occurs following extended periods of ischemia. We hypothesized that the soleus (Sol) muscle, a predominantly slow-twitch muscle, would be less vulnerable to tourniquet-induced ischemia-reperfusion than the plantaris (Plant), a predominan...

Numerous studies have suggested that muscle atrophy is accompanied by apoptotic loss of myonuclei and therefore recovery would require replenishment by muscle stem cells. We used in vivo time-lapse microscopy to observe the loss and replenishment of myonuclei in murine muscle fibers following induced muscle atrophy. To our surprise, imaging of single fibers for up to 28 days did not support the...

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...

The speed with which muscle energetic status recovers after exercise is dependent on oxidative capacity and vascular O(2) pressures. Because vascular control differs between muscles composed of fast- vs. slow-twitch fibers, we explored the possibility that microvascular O(2) pressure (Pmv(O(2)); proportional to the O(2) delivery-to-O(2) uptake ratio) would differ during recovery in fast-twitch ...

Citation: Tricarico D and Mele A (2017) Commentary: A BK (Slo1) channel journey from molecule to physiology. and co-authors in their review paper deal with the hallmarks of big Ca 2+-activated K + (BK) channel biophysics and its physiological impact on specific cells and tissues, highlighting its relationship with auxiliary subunit expression (Contreras et al., 2013). However, the molecular asp...

Wright, David C., Paige C. Geiger, John O. Holloszy, and Dong-Ho Han. Contractionand hypoxia-stimulated glucose transport is mediated by a Ca -dependent mechanism in slow-twitch rat soleus muscle. Am J Physiol Endocrinol Metab 288: E1062–E1066, 2005. First published January 18, 2005; doi:10.1152/ajpendo.00561.2004.—Increases in contraction-stimulated glucose transport in fast-twitch rat epitroc...

Interactions between physiological stimulus frequencies, fascicle lengths and velocities were analyzed in feline caudofemoralis (CF), a hindlimb skeletal muscle composed exclusively of fast-twitch ®bers. Split ventral roots were stimulated asynchronously to produce smooth contractions at sub-tetanic stimulus frequencies. As described previously, the peak of the sub-tetanic force-length relation...

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 ...