Contraction in intact pig aortic strips is not always associated with phosphorylation of myosin light chains.
Intact pig aortic strips were incubated in medium containing [32P]P1 and various Ca2+ concentrations. The 32P content of the myosin P-light chain was determined by radioautography after electrophoresis in the presence of sodium dodecyl sulphate. Although treatment of the strips with noradrenaline always caused a rise in tension, this was not necessarily accompanied by increased phosphorylation of the P-light chain. These results indicate that, in aortic smooth muscle, phosphorylation of the P-light chain is not obligatory for contraction.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D009218:Myosins / Q000378:metabolism*; D010766:Phosphorylation; D013552:Swine
D009218:Myosins; D002118:Calcium