Site of the muscle cell abnormality in swine susceptible to malignant hyperpyrexia.

In vitro studies, using agents which act specifically on different parts of the muscle contractile mechanism, suggest that the abnormality in malignant hyperpyrexia susceptible (MHS) swine muscle lies distal to the postjunctional membrane, and that it is not a result of widespread acetylcholine receptors throughout the muscle membrane. Two possible sites are involved, one being the sarcolemma and the T-system, the other the excitation-contraction coupling mechanism and the sarcoplasmic reticulum.