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...

Medical issues in manned spaceflight fall into several broad categories. One of the most dramatic effects is in the musculoskeletal system, where the abrupt loss of weight bearing leads to dramatic wasting of the gravity bearing muscles (legs and back) and a gradual conversion of slow twitch fibers to fast twitch fibers. This leads to reduction in force generation and the need for greater neura...

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...

Epigenetics is getting increased attention in the analysis of skeletal muscle adaptation to physiological stimuli. In this review, histone modifications muscles and their role regulation characteristics adaptive changes are highlighted. The distribution active modifications, such as H3K4me3 H3 acetylation, largely differs between fast- slow-twitch muscles. It also indicated that transcriptional...

Cytochrome c protein and mRNA are 300 and 100% higher, respectively, in the soleus muscle (predominantly slow-twitch oxidative) than the white vastus lateralis (predominately fast-twitch glycolytic) muscle (W. W. Winder, K. M. Baldwin, and J. O. Holloszy. Eur. J. Biochem. 47: 461-467, 1974; M. M. Lai and F. W. Booth. J. Appl. Physiol. 69: 843-848, 1990). However, the mechanisms controlling thes...

Androgens promote anabolism in skeletal muscle; however, effects on subsequent muscle function are less well defined because of a lack of reliable experimental models. We established a rigorous model of androgen withdrawal and administration in male mice and assessed androgen regulation of muscle mass, structure, and function. Adult C57Bl/6J male mice were orchidectomized (Orx) or sham-operated...

A robust infrastructure for solving time-dependent diffusion using the finite element package FEtk has been developed to simulate synaptic transmission in a neuromuscular junction with realistic postsynaptic folds. Simplified rectilinear synapse models serve as benchmarks in initial numerical studies of how variations in geometry and kinetics relate to endplate currents associated with fast-twi...

Slow, non-twitch muscles are widespread in lower vertebrates and invertebrates and are often assumed to be primarily involved in posture or slow motor patterns. However, in several preparations, including some well known invertebrate "model" preparations, slow muscles are driven by rapid, rhythmic inputs. The response of slow muscles to such inputs is little understood. We are investigating thi...

Genes can be activated or inhibited by signals within the tissues in response to an acute bout of exercise. It is unclear how a particular aerobic exercise bout may influence two muscles with similar actions to the activity. Therefore, the purposes of this investigation was to determine the gene response of selected genes involved in the "stress" response of the gastrocnemius (fast-twitch) and ...

In an attempt to clarify the function of the suboccipital muscles, we performed morphological observation of the suboccipital muscles for variations in the muscle belly and compared the morphology of their muscle fibers in terms of cross-sectional area by immunostaining with anti-myosin heavy chain antibodies. The cadavers of 25 Japanese individuals were used: 22 for morphological examinations ...