Heavy metals induce rapid calcium release from sarcoplasmic reticulum vesicles isolated from skeletal muscle.

Abstract

Micromolar concentrations of Hg, Ag and other reagents known to react with SH-groups stimulate ATPase activity and inhibit active Ca uptake in sarcoplasmic reticulum vesicles derived from rabbit fast skeletal muscle. These effects are caused by a dramatic increase in the Ca permeability of the sarcoplasmic reticulum. Measurements of Ca2+ permeability were made using both isotopes and by spectrophotometric techniques using the Ca2+ indicator arsenazo III. Air oxidation of a SH-group to a disulfide group also leads to a large increase in the Ca permeability of the sarcoplasmic reticulum.