Submandibular secretion in the dog after intraluminal injections of amiloride

Abstract The effects of amiloride on flow rate, osmolarity, Na + , K + and Cl − concentrations were studied in the submandibular glands of dogs. The drug was injected in a retrograde fashion into the duct system of the gland, which was subsequently stimulated to secrete with pilocarpine. In concentrations of 10 −4 and 10 −3 M, amiloride increased the Na + concentration but did not significantly alter the K + concentration of saliva. A slight decrease in Cl − concentration was observed at high flow rates after 10 −4 M amiloride, but otherwise the drug did not significantly affect the Cl − concentration of stimulated salivary secretion. The diuretic has a measurable mucosal (luminal) effect on Na + transport in dog submandibular gland, which is similar to that reported in amphibian epithelia. Its lack of effect on K + excretion differs from findings reported in other epithelial structures, where it has a marked K + -sparing effect. The drug increased the salivary osmolarity in a fashion similar to Na + , a finding that suggests a dissociation between Na + and water transport in salivary duct epithelium.