Influence of pilocarpine on transport by salivary gland slices

Abstract

Effects of pilocarpine on net movements of water and electrolytes in gland cells were investigated in vitro, using slices from sub-maxillary gland of rat. Slices were depleted of K, and loaded with Na, Cl, and water, by incubation in Krebs-Ringer phosphate with nitrogen atmosphere. After this, the slices were transferred to Krebs-Ringer phosphate with oxygen atmosphere. During this period with O2, pilocarpine caused apparent loss of water from cells, since tissue total water decreased and inulin space remained almost unchanged. Without pilocarpine during this time, water in cells increased. Electrolyte movements were also affected by pilocarpine. Specifically, there occurred reduction in net accumulation of K in total tissue and cells. Reduction in net extrusion of Na was suggested. Since, in vivo, an early effect of stimulation involves depletion of gland K, it appears that the current observations have relevance to normal secretion to the extent, at least, that in both circumstances stimulating agents reduce the ability of the cells to maintain stores of K.