The intracellular signals that mediate skeletal muscle protein loss and functional deficits due to muscular disuse are just beginning to be elucidated. Previously we showed that the activity of an NF-kappaB-dependent reporter gene was markedly increased in unloaded muscles, and p50 and Bcl-3 proteins were implicated in this induction. In the present study, mice with a knockout of the p105/p50 (...

PURPOSE To examine the changes of taurine concentrations in blood and skeletal muscles after transient exercise. METHODS Rats were placed on a treadmill set at 25 m.min-1. The animals were divided into four groups: control (no exercise) and exercise groups 1, 2, and 3. The exercise duration for groups 1, 2, and 3 was 30, 60, and 100 +/- 12.5 min (to exhaustion: mean +/- SD), respectively. We ...

BARNARD, R. JAMES, V. REGGIE EDGERTON, TETSUO FURUKAWA, AND J. B. PETER. Histochemical, biochemical, and contractile properties of red, white, and intermediate jibers. Am. J. Physiol. 220 (2) : 41 O-41 4. 197 1 .-Individual fibers from guinea pig muscles (soleus, flexor hallucis longus (FHL), flexor digitorium longus (FDL), medial gastrocnemius (MG) and the portion of the vastus lateralis (RV) ...

The objective of this study was to determine if levels of repressors to myogenic regulatory factors (MRFs) differ between muscles from young adult and aged animals. Total RNA from plantaris, gastrocnemius, and soleus muscles of Fischer 344 x Brown Norway rats aged 9 mo (young adult, n = 10) and 37 mo (aged, n = 10) was reverse transcribed and then amplified by PCR. To obtain a semiquantitative ...

Our objectives were to examine the effects of prerigor excision and rapid chilling vs. conventional carcass chilling of two muscles on proteolysis and tenderness during the postmortem storage, as well as the effects of fast and slow rates of cooking on myofibrillar characteristics and tenderness. The longissimus thoracis (LT) and triceps brachii (TB), long head muscles were removed 45 min after...

We have examined the efficiency of vertebrate striated muscle at two different organizational levels: whole animals and isolated muscles. Terrestrial locomotion is used as a model of 'normal' muscular contraction; animal size and running speed are used as independent variables in order to change either the metabolic requirements of the muscles or the mechanical power production by the muscles o...

The topographical distribution of different fibre types was quantitatively determined within muscles of the lower hindlimb in rabbits and mice. The results were compared to those previously obtained, using the same new quantification methods, in homologous muscles of the rat. “Slow” type I fibres were identified and mapped out in crosssections stained for myofibrillar ATPase (in “slow” soleus d...

The influence of innervation on primary and secondary myogenesis and its relation to fiber type diversity were investigated in two specific wing muscles of quail embryo, the posterior (PLD) and anterior latissimus dorsi (ALD). In the adult, these muscles are composed almost exclusively of pure populations of fast and slow fibers, respectively. When slow ALD and fast PLD muscles developed in ovo...

Functional properties of in situ mitochondria and of mitochondrial creatine kinase were studied in saponin-skinned fibers taken from normal and M-creatine kinase-deficient mice. In control animals, apparent Km values of mitochondrial respiration for ADP in cardiac (ventricular) and slow-twitch (soleus) muscles (137 +/- 16 microM and 209 +/- 10 microM, respectively) were manyfold higher than tha...

Mammals exhibit marked morphological differences in the muscles surrounding the jaw bone due to differences in eating habits. Furthermore, the myofiber properties of the muscles differ with function. Since the muscles in the oral region have various functions such as eating, swallowing, and speech, it is believed that the functional role of each muscle differs. Therefore, to clarify the functio...