[Permeabilized salivary gland cells as a model to study Ca2+-transporting systems of endoplasmic reticulum membrane].

A method for chemical permeabilization of secretory cells of rat submandibular salivary gland has been elaborated. It was shown that the effects of digitonin on total calcium content in permeabilized acinar cells and protein content in their incubation medium correlated with concentration and duration of the detergent treatment. Digitonin-permeabilized acinar cells perform Ca(2+)-dependent protein secretion, which level depends on the duration of cell incubation in an intracellular buffer solution. The ability of permeabilized acinar cells to perform thapsigargin-sensitive ATP-dependent Ca2+ transport was established by using biochemical approaches and monitoring of the intrareticular calcium concentration with mag-fura 2 dye. Thapsigargin-insensitive Ca2+ store in the permeabilized acinar cells of the salivary gland was shown to be also available. Thus, these data give evidence to conclude that digitonin-permeabilized secretory cells of the submandibular salivary gland are an adequate model to study the mechanisms of Ca(2+)-dependent control of the exocytosis and membrane Ca(2+)-transporting systems of the intracellular calcium stores.