Search results for "gastrocnemius muscle"
showing 10 items of 27 documents
NO synthase II in mouse skeletal muscle is associated with caveolin 3
1999
The inducible-type NO synthase (NOS II; iNOS) is constitutively expressed in slow-twitch skeletal muscle fibres of guinea-pigs [Gath, Closs, Gödtel-Armbrust, Schmitt, Nakane, Wessler and Förstermann (1996) FASEB J. 10, 1614-1620]. Here we studied the expression of NOS II in skeletal muscle of wild-type and NOS II-deficient mice and investigated the molecular basis for the membrane association of this NOS in muscle. A basal expression of NOS II mRNA and protein was detected in skeletal muscle from untreated wild-type mice; expression increased when mice were treated with bacterial lipopolysaccharide (LPS). No NOS II was found in any tissue of untreated or LPS-treated NOS II-deficient mice. I…
Non-uniform displacement and strain between the soleus and gastrocnemius subtendons of rat Achilles tendon
2018
Achilles tendon (AT) comprises of 3 subtendons arising from the soleus (SOL) and the lateral (LG) and medial (MG) heads of the gastrocnemius muscle. While recent human studies show differential displacement within AT, these displacements have not been attributed to specific subtendons. We tested the hypothesis that the SOL and LG subtendons show differential displacement and strain during various combinations of SOL, LG, and MG excitations. Movement of knots, sutured onto SOL and LG subtendons of 12 Wistar rats, was videotaped, while the muscles were stimulated intramuscularly and ankle torque was assessed. When SOL only was stimulated, the plantar flexion torque was the smallest among the …
Plantarflexor Muscle-Tendon Properties are Associated With Mobility in Healthy Older Adults
2015
BACKGROUND: Muscle mass, strength, and power are known determinants of mobility in older adults but there is limited knowledge on the influence of muscle architecture or tendon properties on mobility. The purpose of this study was to examine the relationship between mobility and plantarflexor muscle-tendon properties in healthy older adults.METHODS: A total of 52 subjects (age 70-81 years) were measured for 6-minute walk test (6MWT), timed "up and go"-test (TUG), isometric plantarflexion strength, Achilles tendon stiffness, triceps surae muscle architecture, lower extremity lean mass, isometric leg extension strength, and leg extension power. Partial correlations and multivariate regression…
Inducible NO synthase II and neuronal NO synthase I are constitutively expressed in different structures of guinea pig skeletal muscle: implications …
1996
The expression of NOS isoforms was studied in guinea pig skeletal muscle at the mRNA and protein level, and the effect of NO on contractile response was examined. Ribonuclease protection analyses demonstrated NOS I and NOS II mRNAs in diaphragm and gastrocnemius muscle. In Western blots, NOS I and NOS II immunoreactivities were found in the particulate but not the soluble fraction of skeletal muscle. NOS activity was found almost exclusively in the particulate fraction. About 50% of this activity was Ca2+ independent. In immunohistochemistry, the anti-NOS I antibody stained distinct membrane regions of muscle fibers. The most intense staining was seen in neuromuscular endplates identified b…
Childhood neuromuscular disease with rimmed vacuoles
1986
A 5-year-old boy suffered from a slowly progressive non-familial neuromuscular disease, clinically marked by generalised muscle weakness, atrophy and hypotonia, a "myopathic" EMG and mildly elevated CK values. His gastrocnemius muscle showed marked myopathy, type I fibre predominance, and numerous "rimmed" vacuoles. This boy's condition is regarded as a childhood neuromuscular disease with rimmed vacuoles.
Effect of xanthine oxidase-generated extracellular superoxide on skeletal muscle force generation
2009
Skeletal muscle contractions increase superoxide anion in skeletal muscle extracellular space. We tested the hypotheses that 1) after an isometric contraction protocol, xanthine oxidase (XO) activity is a source of superoxide anion in the extracellular space of skeletal muscle and 2) the increase in XO-derived extracellular superoxide anion during contractions affects skeletal muscle contractile function. Superoxide anion was monitored in the extracellular space of mouse gastrocnemius muscles by following the reduction of cytochrome c in muscle microdialysates. A 15-min protocol of nondamaging isometric contractions increased the reduction of cytochrome c in microdialysates, indicating an …
Exercise and recovery in frog muscle: metabolism of PCr, adenine nucleotides, and related compounds
1996
The effects of exercise (swimming), fatigue, and recovery on the intracellular pH (pHi), energy-rich phosphates, and related metabolites were studied in the gastrocnemius muscle of common frogs (Rana temporaria) at 20 degrees C. Exercise caused a rapid decrease in the content of phosphocreatine (PCr) and a corresponding increase in that of Pi. The ATP level remained virtually constant for 1 min; its precipitous decrease during the following minute was associated with a rise in the contents of inosine 5'-monophosphate (IMP) and NH4+, indicating a marked activation of AMP deaminase. Five minutes of swimming caused severe fatigue, which was correlated with decreases in muscle PCr (-85%), ATP …
Muscle enzyme adaptations to added load during training and nontraining hours in rats.
1991
The effects of added load (20% of body mass) on the selected enzyme activities of red and white quadriceps femoris (QF), soleus, and gastrocnemius muscles of rats were studied. The rats were divided into sedentary control (SC), sedentary control with added load (SC+AL), endurance training (ET), and endurance training with added load (ET+AL) groups (n = 10 rats/group). After 6 wk, the SC+AL group had 57% higher (P less than 0.001) beta-glucuronidase (beta-GU) activity and 24% lower (P less than 0.05) citrate synthase activity in white QF than SC. Citrate synthase activity was also decreased in red QF (P less than 0.05) after the added load was used during nontraining hours. The training wit…
Effects of endurance training on alkaline protease activities in rat skeletal muscles.
1983
This study aimed at comparing the effects of running and swimming training protocols and the termination of training on the activities of two proteases with alkaline pH-optima (alkaline protease and myofibrillar protease) in the tibialis anterior, soleus, and gastrocnemius muscles of male rats. The training on treadmill decreased the activities of alkaline and myofibrillar proteases by approx. 10-20% in the muscles studied. The activities of both proteases were unchanged in swimming-trained rats. Two weeks after the termination of running training the activity of alkaline protease was increased in gastrocnemius muscle but not in the other muscles. Swimming training increased the activity of…
Muscle fascicle and tendon behavior during human locomotion revisited.
2008
High-speed ultrasonography has revealed that, in human locomotion, the nature of fascicle and tendon length changes varies depending on the task, contraction intensity, and the muscles involved. The findings emphasize that the active fascicles of the gastrocnemius muscle are suddenly stretched, although they are shortening. This short-lasting stretch triggers the stretch reflex, timing of which is dependent on running speed.