Partial dissociation between salivary secretion and active potassium transport in the perfused cat submandibular gland

Publisher Website
Google Scholar
Abstract
Summary Isolated cat submandibular glands were perfused with Locke solutions in a thermostated chamber. Passive loss of potassium and uptake of sodium was achieved either by increasing the permeability of the cell membranes by acetylcholine (ACh) or by inhibiting the sodium-potassium pump reversibly by cooling or by removal of extracellular potassium. Irrespective of the way by which the cells were potassium depleted and sodium loaded, re-establishment of normal conditions was sufficient to cause an active net uptake of potassium (probably coupled to net extrusion of sodium). However, while ACh-induced changes in intracellular concentrations of monovalent cations were accompanied by salivary secretion, virtually no secretion was observed when normal conditions were re-established after concentration changes caused by inhibiting the sodium-potassium pump. It is concluded that while the transport mechanisms responsible for the maintenance of the intracellular concentrations of monovalent cations undoubtedly is a (Na+−K+)-activated ATPase, the transport mechanism responsible for the formation of the primary saliva is probably of a different type, since it apparently is not directly activated by the intracellular sodium concentration.