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ELECTROLYTE SECRETION BY RAT SALIVARY GLANDS IN VIVO AND IN VITRO

1964; Elsevier BV; Linguagem: Inglês

10.1016/b978-1-4832-2871-6.50021-7

Leon H. Schneyer, C. A. Schneyer,

Neuroscience and Neuropharmacology Research

Salivary secretion has been investigated, in the rat, in vivo and in incubated gland slices, with the ultimate objective of delineating mechanisms of transport of fluid and electrolytes. As an initial phase of the work, electrolyte composition was investigated in the major salivary secretions and in the salivary glands themselves. In glands, composition was determined for the whole organ and, by means of "space" studies, for the salivary gland cells. Following this phase, transport mechanisms were investigated in vitro, using slices of submaxillary gland. With slices, cells could be loaded with sodium and depleted of potassium during aerobic or, to appreciably greater extent, during anaerobic incubation. Reaccumulation of cell potassium and extrusion of sodium were consistently observed when oxygen was readmitted after anaerobic incubation. It was noted that these exchanges occurred against chemical and electrical potential gradients. Chloride was accumulated by cells during anaerobic incubation but was not extruded when oxygen was readmitted. Active transport of sodium and potassium, but not of chloride, were, thus, established for rat submaxillary gland cells. Preliminary data suggested that stimulation by pilocarpine reduced the net efflux of sodium and the net influx of potassium during aerobic incubation following anaerobiosis, that is, in a situation where these net fluxes involve active transport of sodium and potassium. Preliminary investigation of one-way movements of ions during this period suggested that pilocarpine increased sodium influx and did not affect sodium efflux or potassium influx. These and other observations are examined in relation to current hypotheses on the mode of formation of a secretory fluid.