title: Effect of transport inhibitors on secretion by perfused rat submandibular gland.
abstract: Ouabain (10(-3) M) caused a 95.8% reduction in the volume of saliva secreted during a 60-min period by the isolated, perfused submandibular gland of the rat exposed to acetylcholine (10(-6) M) and modified salivary cation (Na and K) concentrations but not salivary Cl concentrations. Furosemide (10(-3) M) caused a 74.9% reduction in saliva volume and significantly reduced salivary Cl concentrations but did not modify salivary Na or K. Ethacrynic acid (10(-4) M) resulted in a 58.6% reduction in saliva volume, increased salivary Na and Cl concentrations, and reduced salivary K+ concentrations at low rates of flow. The results suggest that an ouabain-sensitive Na+-K+-ATPase and a furosemide-sensitive NaCl cotransport system contribute to acetylcholine-induced fluid secretion in the rat submandibular gland. The Na+-K+-ATPase probably provides the energy or driving force for the NaCl cotransport system by maintaining a Na+ gradient in the salivary cells. The lesser effect of ethacrynic acid on saliva volumes may result from a quantitatively smaller action on the same NaCl cotransport affected by furosemide. An ouabain-sensitive pump present in salivary ducts regulates transductal transport of Na and K.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D005665:Furosemide / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D010042:Ouabain / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012463:Saliva / Q000187:drug effects / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013363:Submandibular Gland / Q000187:drug effects / Q000378:metabolism*
chemical_list: D010042:Ouabain; D005665:Furosemide; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D000109:Acetylcholine; D011188:Potassium