The properties of serotonin accumulation by rat extensor digitorum longus muscles have been characterized. No evidence was found for an active transport process because serotonin accumulation was unaffected by ouabain, metabolic inhibitors, or structural analogs. Serotonin transport was dependent on temperature and the external concentration of serotonin, was not saturable, and accumulated two- to threefold higher than urea. These findings suggest that serotonin transport into skeletal muscle is mediated via passive diffusion followed by tissue binding. In vivo imipramine and chlorpheniramine, drugs which given with serotonin produce an acute myopathy, also inhibited its accumulation by rat extensor digitorium longus muscles. This supports the notion that the myopathy produced by serotonin plus membrane-active drugs may be mediated by the action of serotonin upon the sarcolemma or upon the skeletal muscle vasculature in combination with the membrane action of imipramine and chlorpheniramine upon skeletal muscle membranes.
ASJC Scopus subject areas
- Developmental Neuroscience