Clenbuterol, a β2-agonist, induces skeletal muscle hypertrophy and a shift from slow-oxidative to fast-glycolytic muscle fiber type profile. However, the cellular mechanisms of the effects of chronic clenbuterol administration on skeletal muscle are not completely understood. As the intracellular Ca2+ concentration must be finely regulated in many cellular processes, the aim of this study was t...

This study aimed to examine whether a single ingestion of arginine activates the mammalian target rapamycin complex 1 (mTORC1) in rat fast- and slow-twitch skeletal muscles. In first experiment, rats were orally administered (3 or 10 mmol/kg body weight) water. The plantaris, gastrocnemius, soleus muscles excised h after administration. Immunoblot analysis showed that administration with higher...

As a postural behavior, gliding and soaring flight in birds requires less energy than flapping flight. Slow tonic and slow twitch muscle fibers are specialized for sustained contraction with high fatigue resistance and are typically found in muscles associated with posture. Albatrosses are the elite of avian gliders; as such, we wanted to learn how their musculoskeletal system enables them to m...

Mammalian skeletal muscles undergo adaptation in response to alteration in functional demands by means of a variety of cellular signaling events. Previous experiments in transgenic mice showed that an active form of Ca2+/calmodulin-dependent protein kinase IV (CaMKIV) is capable of stimulating peroxisome proliferator-activated receptor gamma-coactivator 1alpha (PGC-1alpha) gene expression, prom...

The aim of the present study was to examine the influence of intermittent hypoxia at rest and in combination with long-term high-intensity swimming exercise on lipid peroxidation and antioxidant defense system adaptation in skeletal muscles differing in fiber type composition. High-intensity chronic exercise was performed as swimming training with load that corresponded to ~ 75 % VO2max (30 min...

Histochemical differentiation of 12 skeletal muscles with a different fibre type composition was studied in miniature pigs from 80 d of gestation to 1 year of age. Two fetal myofibre types were distinguished at 100 d of gestation by the mATPase reaction after acid preincubation. The staining for oxidative enzyme activities showed no conspicuous differences between fibres up to the 6th day after...

Gordon, Scott E., Martin Flück, and Frank W. Booth. Selected Contribution: Skeletal muscle focal adhesion kinase, paxillin, and serum response factor are loading dependent. J Appl Physiol 90: 1174–1183, 2001.—This investigation examined the effect of mechanical loading state on focal adhesion kinase (FAK), paxillin, and serum response factor (SRF) in rat skeletal muscle. We found that FAK conce...

Rat extensor digitorum longus muscles were transversely sliced into 7-8 segments. The muscle slices were autografted back into their original beds. In one series the recipient limbs were normal and in the other, limbs were denervated. At postoperative intervals of 7, 14, 30, and 60 days, the contractile properties (latency period, contraction and half relaxation times, time parameters of contra...