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Lacrimal gland electrolyte and water secretion in the rabbit: localization and role of (Na+ + K+)‐activated ATPase.
Author(s) -
Dartt D A,
Møller M,
Poulsen J H
Publication year - 1981
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1981.sp014002
Subject(s) - ouabain , secretion , chemistry , medicine , endocrinology , bicarbonate , atpase , lacrimal gland , biophysics , acetazolamide , sodium , biology , biochemistry , enzyme , organic chemistry , pathology
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.