[Effects of amrinone on the Ca(2+)-related functions of skinned skeletal muscle fibers of guinea pigs]

Abstract

In malignant hyperthermia (MH) patients, the rate of Ca(2+)-induced Ca2+ release (CICR) from the sarcoplasmic reticulum (SR) has been reported to be enhanced. The effects of amrinone on the Ca(2+)-related functions (CICR, Ca2+ uptake by the SR and Ca2+ sensitivity of the contractile system) of the skeletal muscle were examined using the chemically skinned fiber technique in the extensor digitorum longus of guinea pigs. Amrinone enhanced the CICR rate in a dose-dependent manner, but not around its clinical concentrations. Ca2+ uptake, initial rate of Ca2+ uptake by the SR and Ca2+ sensitivity of the contractile system were not affected at 1 mM of amrinone. These results suggest that amrinone may be clinically safe to use in MH susceptible patients.