Fura-2 detected myoplasmic calcium and its correlation with contracture force in skeletal muscle from normal and malignant hyperthermia susceptible pigs.
Fura-2 was used to estimate myoplasmic [Ca2+] in intact intercostal muscle fibers from normal and malignant hyperthermia susceptible (MHS) pigs. Small muscle bundles (20-50 fibers) were loaded with the membrane-permeant form of the dye. Resting myoplasmic [Ca2+] were not significantly different in normal and MHS muscles. Halothane produced increases in myoplasmic Ca2+ with associated contractures in MHS muscles, but not in normal muscles. These halothane effects were reversible. Caffeine produced increases in myoplasmic Ca2+ and contractures in both MHS and normal muscles. The threshold concentrations were lower in the MHS muscles. The correlations between myoplasmic [Ca2+] and force in MHS and normal muscles were similar.
Iaizzo
P A
PA
Neuroiogische Klinik, Technischen Universität München, Federal Republic of Germany.
Klein
W
W
Lehmann-Horn
F
F
D000818:Animals; D001572:Benzofurans; D002110:Caffeine / Q000008:administration & dosage / Q000494:pharmacology; D002118:Calcium / Q000032:analysis*; D004198:Disease Susceptibility; D016257:Fura-2; D006221:Halothane / Q000008:administration & dosage / Q000494:pharmacology; D008305:Malignant Hyperthermia / Q000378:metabolism / Q000503:physiopathology*; D009119:Muscle Contraction; D009132:Muscles / Q000032:analysis*; D005082:Physical Exertion; D013552:Swine
D001572:Benzofurans; D002110:Caffeine; D002118:Calcium; D016257:Fura-2; D006221:Halothane