Chloride transport in a human submandibular gland cell line studied by X-ray microanalysis

Ion transport properties of the human submandibular gland cell line A253 were investigated by X-ray microanalysis. The cells were grown on ultrathin plastic films on titanium grids. After the experiment, where the cells were exposed to various agonists and inhibitors, the specimens were briefly rinsed in distilled water, frozen, and freeze-dried. The elemental composition of the cultured cells most closely resembled that of striated duct cells. Beta-adrenergic stimulation caused a small decrease in the cellular Cl- and K+ concentration, but cholinergic stimulation had no effect. Also stimulation with cAMP caused a decrease in Cl- and K+; this decrease could be inhibited by the chloride channel blocker NPPB. Loss of Cl- and K+ could also be elicited by exposure to a hypotonic solution. The results suggest that there may be several types of chloride channel present in A253 cells.