Abstract
In preceding papers (1, 2), we reported that acetylcholine, excess K+ or noradrenaline in the presence of Ca2+ caused secretion of amylase from slices of parotid glands and release of amylase from zymogen granules, consisting mainly of stored amylase. Moreover, ATP and a low concentration of Ca2+ were also important in the process of secretion. Accordingly, there is some secretory process inside the cell which is regulated by Ca2+.
It has also been reported that the release of catecholamine from chromaffin granules (3-5) and of acetylcholine from synaptic vesicles were caused by ATP (6). Oka et al. (7) also suggested that the release of catecholamine from chromaffin granules is associated with a change in structure of the granules.
In the present work, we investigated the effect of a low concentration of Ca2+ on the structure of zymogen granules to clarify the relation between release of amylase from the granules and their change in structure.
