title: Transient effect of intracellular dantrolene on E--C coupling in skeletal muscle.
abstract: The effect of dantrolene-Na (DAN) on electrical and mechanical responses was investigated to single fibers of frog semitendinosus. Twitch tension was potentiated over 2--4 min by intracellular application of DAN and was rapidly decreased thereafter. Extracellular DAN depressed the tension with all dosages used. Although DAN had no effect on membrane potential, it exerted a biphasic action on membrane excitability. From these results, a mechanism is postulated for the release of trigger Ca2+ from T-tubules.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001001:Anura; D002118:Calcium / Q000494:pharmacology; D003620:Dantrolene / Q000494:pharmacology*; D006827:Hydantoins / Q000494:pharmacology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects*; D009132:Muscles / Q000187:drug effects; D011898:Ranidae
chemical_list: D006827:Hydantoins; D003620:Dantrolene; D002118:Calcium