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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Carbonic anhydrase III (EC 4.2.1.1) is the most abundant cytosolic protein in type I skeletal muscle fibers. Investigations of its physiological role have mostly been conducted with rat muscles, which sometimes are unsuitable for in vitro studies. The objective of the present study was to characterize the carbonic anhydrase in the mouse soleus muscle to verify if this muscle can be used as a model to further study the enzyme's function. Total carbonic anhydrase specific activity in the mouse soleus was comparable to the value for rat. However, 60% of the total carbonic anhydrase activity in the mouse was of the sulfonamide-sensitive type and, therefore, not related to carbonic anhydrase III. Electrophoretic analysis revealed the presence of a 29-kDa protein in total and cytosolic extracts of the mouse soleus. Immunoblotting with an antibody developed against rat carbonic anhydrase III showed that it was also specific for this 29-kDa peptide, which presumably is the mouse carbonic anhydrase III. Inhibition of the sulfonamide-sensitive activity had no effect on contractile and fatigue characteristics, whereas inhibition of the sulfonamide-resistant carbonic anhydrase III activity led to a significant increase in resistance to fatigue. We conclude that the mouse soleus may represent an excellent model to understand the contribution of different carbonic anhydrase isoforms to muscle physiology.
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PMID:Carbonic anhydrase in mouse skeletal muscle and its influence on contractility. 784 Sep 45

Inhibition of carbonic anhydrase III (CA III; EC 4.2.1.1) activity in type I muscle can influence resistance to fatigue and glycogen utilization. Our aim was to determine if CA III inhibition could influence muscle pH and glycolytic rate. Muscle pH, hexosemonophosphates (HMP), glycolytic intermediates, ATP, and creatine phosphate (CP) were measured at rest and during a fatigue protocol in rat soleus muscles in vitro with or without CA inhibitors (CAI). In resting muscles, CAI resulted in a significant drop in pH (7.11 vs. 7.06, P < 0.05) and in a two- to threefold increase in HMP content compared with control muscles. Measurements of HMP and glycolytic intermediates during the fatigue protocol suggested, however, that the glycolytic flux was not influenced. Globally, muscles incubated with CAI showed larger perturbations of their CP and ATP content than control muscles. The accumulation of HMP induced by the CAI was found to be totally dependent on the combined presence of external glucose and contractile activity, suggesting that inhibiting CA III may augment the responsitivity of the contraction-induced glucose uptake process.
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PMID:Carbohydrate utilization in rat soleus muscle is influenced by carbonic anhydrase III activity. 936 82

Oxidative slow skeletal muscle contains carbonic anhydrase III in high concentration, but its primary function remains unknown. To determine whether its lack handicaps energy metabolism and/or acid elimination, we measured the intracellular pH and energy phosphates by (31)P magnetic resonance spectroscopy in hind limb muscles of wild-type and CA III knockout mice during and after ischemia and intense exercise (electrical stimulation). Thirty minutes of ischemia caused phosphocreatine (PCr) to fall and P(i) to rise while pH and ATP remained constant in both strains of mice. PCr and P(i) kinetics during ischemia and recovery were not significantly different between the two genotypes. From this we conclude that under neutral pH conditions resting muscle anaerobic metabolism, the rate of the creatine kinase reaction, intracellular buffering of protons, and phosphorylation of creatine by mitochondrial oxygen metabolism are not influenced by the lack of CA III. Two minutes of intense stimulation of the mouse gastrocnemius caused PCr, ATP, and pH to fall and ADP and P(i) to rise, and these changes, with the exception of ATP, were all significantly larger in the CA III knockouts. The rate of return of pH and ADP to control values was the same in wild-type and mutant mice, but in the mutants PCr and P(i) recovery were delayed in the first minute after stimulation. Because the tension decrease during fatigue is known to be the same in the two genotypes, we conclude that a lack of CA III impairs mitochondrial ATP synthesis.
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PMID:A quantitative study of bioenergetics in skeletal muscle lacking carbonic anhydrase III using 31P magnetic resonance spectroscopy. 1718 36

Fatigue, defined as the failure to maintain the required or expected power output, is a complex problem. Its occurrence mechanism is extremely complicated. The obvious reasons are that it is a multifactorial situation and that the limiting factors may vary with force intensity, exercise duration and muscle type. In recent years, it has been found that carbonic anhydrase III(CAIII) which is present in high concentrations in muscles has multiple biological activities that can dissipate or resist some fatigue related substances. Therefore, we hypothesize that the CAIII supplementation may contribute to dissipate fatigue. Confirmation of this hypothesis will further add to our understanding of the physiological functions of CAIII and will be hopeful to solve the difficulties in eliminating muscular fatigue.
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PMID:Carbonic anhydrase III: the new hope for the elimination of exercise-induced muscle fatigue. 1913 7