| Abstract: | Since increased intracellular Ca2+ is believed to be the main factor causing skeletal muscle contracture in human and porcine malignant hyperthermia, the potential effects of the ionophore A23187, which enhances intracytoplasmic Ca2+, were investigated in Pietrain pig muscles. These effects were compared with those of caffeine, known to induce dose-dependent contracture in vitro in isolated muscle from human subjects with malignant hyperthermia. For this purpose, the mechanical and biochemical actions of caffeine and A23187 were tested in intercostal muscle biopsies from 10 normal pigs and 10 with malignant hyperthermia. The results show that A23187 allowed very clear differentiation between the muscles of normal and pathological animals. In view of the wide spectrum of drug sensitivity characterizing subjects with malignant hyperthermia, it is suggested that exposure to A23187 be added to the halothane and caffeine tests currently used to detect this disease. |
