Ultrastructural localization of Ca2+ in the Golgi apparatus of two different cell types

The precipitation reaction with potassium oxalate was used to investigate the subcellular localization of Ca2+ in atrial myocardocytes and in Schwann cells of non-myelinated nerve fibers. Chelation with EGTA was used to prove the presence of Ca2+ in the electronoopaque deposits. In both cell types the oxalate reaction was intense in the classically described Ca2+ deposits: the perinuclear cisterna, the endo (sarco) plasmic reticulum, the mitochondrial matrix, but also in a novel localization: the cisternae of the Golgi stack in all cis to trans positions, suggesting that Golgi Apparatus is a major intracellular Ca2+ pool.