Ion-induced release of calcium from isolated sarcoplasmic reticulum

Choline Cl addition to either longitudinal reticulum or terminal cisternae of skeletal muscle sarcoplasmic reticulum caused release of Ca2+ which had previously accumulated in the presence of ATP. However the extent of release was considerably greater in terminal cisternae. Ca2+ accumulation and release by terminal cisternae were also observed using chlorotetracycline as a probe for membrane-associated Ca2+. Among a number of salts and ions tested for effectiveness in causing Ca2+ release the order was gluconate−