Lacrimal gland electrolyte and water secretion in the rabbit: localization and role of (Na+ + K+)-activated ATPase.
1. The rate of acetylcholine (ACh)-induced fluid secretion was measured from the main secretory duct of rabbit lacrimal glands perfused in vivo with Krebs Henseleit bicarbonate solutions. 2. Perfusion with ouabain (10(-5) M) decreased the rate of lacrimal gland fluid secretion to 23% of the control value. 3. Perfusion with furosemide (10(-4) and 10(-3) M), which has been shown to inhibit the coupled transport of Na+ and Cl-, reversibly decreased the rate of secretion to 43 and 33% of the control value respectively. 4. (Na+ + K+)-activated ATPase was localized in slices of rabbit lacrimal gland using autoradiography with [3H]ouabain. 5. A high density of [3H]ouabain binding sites was present on ductal cells, whereas a very low density was found on acinar cells. For both types of cells the [3H]ouabain binding sites were located on the basolateral plasma membranes. 6. It is concluded that ACh-induced secretion of electrolytes and water is dependent upon (Na+ + K+)-activated ATPase. In addition, coupled transport of Na+ and Cl- appears to be involved in secretion. 7. Basolateral location of the (Na+ + K+)-activated ATPase implies that it plays an indirect role in electrolyte and water secretion. A possible role may be to energize a secondary active transport of Cl- that is mediated by a NaCl cotransport system.
D000109:Acetylcholine / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001345:Autoradiography; D005665:Furosemide / Q000494:pharmacology; D066298:In Vitro Techniques; D007765:Lacrimal Apparatus / Q000187:drug effects / Q000378:metabolism*; D008954:Models, Biological; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D011817:Rabbits; D012636:Secretory Rate / Q000187:drug effects; D012964:Sodium / Q000378:metabolism*; D013666:Tears / Q000378:metabolism
D010042:Ouabain; D005665:Furosemide; D012964:Sodium; D000251:Adenosine Triphosphatases; D000109:Acetylcholine; D011188:Potassium