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Cross talk between the intrarenal doparninergic and cyclooxygenase-2 systems.
- Source :
-
American Journal of Physiology: Renal Physiology . Apr2005, Vol. 288, pF840-F845. 6p. 2 Diagrams, 1 Chart, 2 Graphs. - Publication Year :
- 2005
-
Abstract
- In mammalian kidney, dopamine produced in the proximal tubule (PT) acts as an autocrine/paracrine natriuretic hormone that inhibits salt and fluid reabsorption in the PT. In high-salt-treated animals, PT dopamine activity increases and inhibits reabsorption, leading to increased salt and fluid delivery to the macula densa (MD) and subsequent natriuresis and diuresis. Regulated cyclooxygenase-2 (COX-2) in the MD represents another Intrinsic system mediating renal salt and water homeostasis. Renal cortical COX-2 is inversely related to salt intake, and decreased extracellular NaCl stimulates COX-2 expression in cultured MD/cortical thick ascending limb cells. The current study investigated interactions between renal dopamine and cortical COX-2 systems. In rats fed a control diet, the dopamine precursor L-dihydroxyphenylalanine (L-DOPA) or the DA1 receptor agonist SKF-81297 suppressed cortical COX-2 expression. High salt suppressed conical COX-2 expression, which was attenuated by inhibition of dopamine production with benserazide or the DA1 receptor antagonist, SCH-23390. In contrast, L-DOPA or the dopamine-metabolizing enzyme inhibitor entacapone suppressed low-salt-induced conical COX-2 expression. Inhibition of PT reabsorption with the carbonic anhydrase inhibitor acetazolamide suppressed cortical COX-2 expression. In contrast, treatment with distally acting diuretics led to elevation of cortical COX-2. These results indicate that dopamine modulates renal cortical COX-2 expression by modifying PT reabsorption. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 1931857X
- Volume :
- 288
- Database :
- Academic Search Index
- Journal :
- American Journal of Physiology: Renal Physiology
- Publication Type :
- Academic Journal
- Accession number :
- 16571288
- Full Text :
- https://doi.org/10.1152/ajprenal.00240.2004