Relationship between length-tension relation and 20,000 dalton myosin light chain phosphorylation in guinea-pig taenia caeci.
1. Relationship between length-tension relation and phosphorylation of 20,000 dalton myosin light chain (LC20) in guinea-pig taenia caeci was investigated. 2. At in situ length (Lb), a good linear correlation was obtained between isometric tension and LC20 phosphorylation in high-K+-stimulated muscle. 3. In 100 mM K+-stimulated muscle, the active tension decreased at muscle lengths other than Lb, but no significant decrease in degree of LC20 phosphorylation was observed. 4. These results suggest that in guinea-pig taenia caeci, the major portion of the decrease in active tension at muscle lengths other than Lb is not due to a decrease in degree of activation.
D000818:Animals; D002432:Cecum / Q000502:physiology*; D006224:Cricetinae; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D015879:Myosin Subfragments; D009218:Myosins / Q000502:physiology*; D010446:Peptide Fragments / Q000502:physiology*; D010766:Phosphorylation; D011188:Potassium / Q000494:pharmacology; D013314:Stress, Mechanical
D015879:Myosin Subfragments; D010446:Peptide Fragments; D009218:Myosins; D011188:Potassium