Metabolic end products inhibit sarcoplasmic reticulum Ca2+ release and [3H]ryanodine binding

Abstract

son. Metabolic end products inhibit sarcoplasmic reticulum Ca2 ’ release and [3H]ryanodine binding. J. Appl. PhysioZ. 78(5): 16651672, 1995.- Sarcoplasmic reticulum (SR) Ca2’ release channel function is modified by ligands (Mg+, Ca2’, ATP, and H’) that are generated during a bout of exercise. We have examined the effects of changing intracellular me-tabolites on Ca2 ’ release, [3H]ryanodine binding, and single-Ca2 ’ release channel activity of SR isolated from white rabbit skeletal muscle. Increasing Mg+ (from 0 to 4 mM) and de-creasing pH (7.1-6.5) inhibited SR Ca2 ’ release and [3H]-ryanodine binding. In addition, increasing lactate concentra-tions from 2 to 20 mM inhibited [3H]ryanodine binding to SR vesicles, inhibited SR Ca2 ’ release, and decreased the single-channel open probability. These findings suggest that intra-cellular modifications that disrupt excitation-contraction cou