title: The effect of dantrolene sodium on the efflux of Ca45 from rat heavy sarcoplasmic reticulum.
abstract: The effect of dantrolene on calcium (Ca2+) efflux was studied using SR vesicles isolated at 8,000 X G from rat skeletal muscle. Dantrolene concentrations of 4 to 9 X 10(-5) M suppressed the efflux of Ca45 from the isolated vesicles in a dose-related way during the first 5 minutes of incubation. The residual Ca2+ in the sarcotubular vesicles was inversely related to the dantrolene concentrations of 4, 6 and 9 X 10(-5) M. The addition of 10mM caffeine to the efflux media offset the suppressive effects of the lower concentrations of dantrolene on Ca2+ efflux. Only dantrolene concentrations of 9 X 10(-5)M resulted in significant retention of Ca2+ in the vesicles in the presence of 10mM caffeine.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003620:Dantrolene / Q000494:pharmacology*; D006614:Hindlimb; D006827:Hydantoins / Q000494:pharmacology*; D066298:In Vitro Techniques; D051381:Rats; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors
chemical_list: D006827:Hydantoins; D003620:Dantrolene; D002118:Calcium