Calcium ATPase in the sarcoplasmic reticulum of muscle from normal and malignant hyperthermia susceptible pigs.
The density of Mg(2+)-dependent Ca2+ ATPase in the terminal cisternae of pig skeletal muscle fibers was investigated to discover whether a reduction in Ca2+ ATPase content impairs Ca2+ sequestration and contributes to the elevated myoplasmic Ca2+ concentration in malignant hyperthermia. Unexpectedly, immunogold electron microscopy showed an increase in Ca2+ ATPase, while densitometry of SDS-polyacrylamide gels suggested that the Ca2+ ATPase content of terminal cisternae vesicles did not change. The affinity of Ca2+ ATPase in vesicles for our monoclonal antibody was not altered. We suggest that the availability of antigenic sites in malignant hyperthermia increases after processing for electron microscopy, perhaps as a consequence of altered sarcoplasmic reticulum membrane properties.
Dulhunty
A F
AF
Division of Neuroscience, John Curtin School of Medical Research, ANU, Canberra City, Australia.
Junankar
P R
PR
Stanhope
C
C
D000818:Animals; D000911:Antibodies, Monoclonal / Q000032:analysis; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D007150:Immunohistochemistry; D008305:Malignant Hyperthermia / Q000201:enzymology*; D016253:Microscopy, Immunoelectron; D009132:Muscles / Q000201:enzymology* / Q000648:ultrastructure; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D013552:Swine
D000911:Antibodies, Monoclonal; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D002118:Calcium