CALCIUM ACCUMULATION BY SARCOPLASMIC-RETICULUM IN WHOLE MUSCLE HOMOGENATE PREPARATIONS OF MALIGNANT HYPERTHERMIA DIAGNOSTIC PATIENTS AND PIGS

Calcium accumulation by the sarcoplasmic reticulum in whole muscle homogenate preparations of malignant hyperthermia‐susceptible (MH+) and non‐susceptible (MH‐) humans and pigs was investigated using a calcium electrode at 35°C. Sarcoplasmic reticulum of MH+ humans and pigs showed normal Ca2+ accumulation, with no difference being observed in the rate and the time taken to achieve maximal accumulation. However, the capacity for Ca2+ accumulation by the sarcoplasmic reticulum in MH+ humans and pigs is considerably less stable than normal after prolonged ageing of the whole muscle homogenate preparations in ice. In MH+ patients, the capacity for Ca2+ accumulation by the sarcoplasmic reticulum showed a decline of 62% at 22 h ageing and 70% at 48 h ageing, as compared with a reduction of only 23% in MH‐ patients. In MH+ pigs, the sarcoplasmic reticulum showed a 96% deterioration in the capacity for Ca2+ accumulation as compared with a loss of only 40% in MH‐ pigs at 7 h ageing in ice. In both humans and pigs, the decline in Ca2+ accumulation was prevented by incubating the whole muscle homogenate preparations for 2 h at 35°C prior to ageing the preparations. The diminished Ca2+ accumulating capacity of the sarcoplasmic reticulum in whole muscle homogenate preparations of MH‐susceptible individuals in our experimental protocol provides a potential diagnostic test for malignant hyperthermia susceptibility. © 1990 Acta Anaesthesiologica Scandinavica Fonden