Calmodulin and malignant hyperpyrexia.

The function of calmodulin as a biological regulator is linked to the level of free Ca2+ in the cell, and there is evidence that calmodulin may itself be involved in the control of the movements of cellular Ca2+. Malignant hyperpyrexia, on the other hand, is caused by a disturbance in the level of myoplasmic Ca2+. We have investigated the possibility that calmodulin may be involved in malignant hyperpyrexia by studying the trifluoperazine-induced inhibition of calmodulin activation by phosphodiesterase, using crude and purified calmodulin preparations from control and MH-susceptible pigs. No abnormality was found in the pattern of either calmodulin activation or trifluoperazine-induced inhibition in MH muscle.