The effect of dantrolene on skeletal-muscle sarcoplasmic-reticulum function in malignant hyperpyrexia in pigs.
The effect of the muscle relaxant dantrolene on isolated sarcoplasmic reticulum was studied in control and malignant-hyperpyrexia-susceptible Landrace pigs. The membranes prepared from both sources showed similar Ca2+-dependent ATPase activities, had comparable phospholipid/protein ratios, and their sodium dodecyl sulphate/polyacrylamide-gel patterns were indistinguishable. Membranes from both sources appeared to bind similar amounts of dantrolene. The drug did not stimulate Ca2+-dependent ATPase activity in preparations from either source. The rates of Ca2+ exchange and Ca2+ efflux appeared to be similar in sarcoplasmic reticulum of control and malignant-hyperpyrexia-susceptible pigs. Dantrolene did not affect either the rates or the amount of Ca2+ lost from the vesicles. These results suggest that dantrolene does not directly affect the movement of Ca2+ across the sarcoplasmic-reticulum membrane.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D003620:Dantrolene / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D008305:Malignant Hyperthermia / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D013552:Swine
D000252:Calcium-Transporting ATPases; D003620:Dantrolene; D002118:Calcium