<b>CHANGES IN THE Ca-INDUCED Ca RELEASE MECHANISM IN THE SARCOPLASMIC RETICULUM OF THE MUSCLE FROM A PATIENT WITH MALIGNANT </b><b>HYPERTHERMIA </b>

Abstract

Changes in skeletal muscle of a patient with malignant hyperthermia (MH) were examined in skinned fibers. In the patient's muscle, the Ca-induced Ca release mechanism showed a significantly higher sensitivity to Ca than that in normal muscles and the maximum rate of Ca release at a sufficiently high concentration of Ca was also significantly higher. Halothane accelerated Ca-induced Ca release to a similar extent both in the patient's and normal muscles. No difference was observed in the properties of Ca uptake by the sarcoplasmic reticulum (SR) and of the contractile protein system between the patient's and normal muscles. The changes observed in the Ca-induced Ca release mechanism were considered to be sufficient to explain the disease.