Inhibition of actomyosin ATPase by high concentrations of 5-hydroxytryptamine. Possible basis of lesion in 5HT-induced experimental myopathy.
The effect of 5-hydroxytryptamine (5HT) on the ATPase activity and sulphydryl group reactivity of mammalian skeletal muscle actomyosin has been studied. 5HT inhibited the Mg2+-activated but not the Ca2+-activated ATPase activity of actomyosin. It slightly activated myosin ATPase. The sulphydryl groups of actomyosin reacting with 5,5'-dithiobis-(2-nitrobenzoic acid) were blocked by concentrations of 5HT which inhibited the Mg2+-activated ATPase. The significance of the results are discussed in relation to the muscle lesions in the experimental myopathy induced by 5HT and imipramine.
D000205:Actomyosin / Q000037:antagonists & inhibitors*; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors*; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002417:Cattle; D004789:Enzyme Activation / Q000187:drug effects; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D009137:Muscular Dystrophy, Animal / Q000139:chemically induced; D012701:Serotonin / Q000494:pharmacology*
D012701:Serotonin; D000205:Actomyosin; D000251:Adenosine Triphosphatases; D008274:Magnesium; D002118:Calcium