Role of PGE(2) in alpha(2)-induced inhibition of AVP- and cAMP-stimulated H(2)O, Na(+), and urea transport in rat IMCD
| Autor: | Alexander J. Rouch, Lúcia H. Kudo |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
medicine.medical_specialty
Vasopressin Arginine Physiology Oxymetazoline Stimulation In Vitro Techniques Dinoprostone Internal medicine medicine Renal medulla Cyclic AMP Animals Urea Prostaglandin E2 Kidney Tubules Collecting Rats Wistar Kidney Medulla Chemistry Sodium Water Biological Transport Thionucleotides Rats Arginine Vasopressin Urea transport medicine.anatomical_structure Endocrinology Eicosanoid Adrenergic alpha-Agonists medicine.drug |
| Zdroj: | American journal of physiology. Renal physiology. 279(2) |
| ISSN: | 1931-857X |
| Popis: | PGE2inhibits osmotic water permeability ( Pf) in the rat inner medullary collecting duct (IMCD) via cellular events occurring after the stimulation of cAMP, i.e., post-cAMP-dependent events. The α2-agonists also inhibit Pfin the rat IMCD via post-cAMP-dependent events. The purpose of this study was to determine whether PGE2plays a role in α2-mediated inhibition of Pf, Na+, and urea transport in the rat IMCD. Isolated terminal IMCDs from Wistar rats were perfused to measure, in separate experiments, Pf, lumen-to-bath22Na+transport ( Jlb), and urea permeability ( Pu). Transport was stimulated with 220 pM arginine vasopressin (AVP) or 0.1 mM 8-(4-chlorophenylthio)-cAMP (CPT-cAMP). Indomethacin was used to inhibit endogenous prostaglandin synthesis, and the α2-agonists clonidine, oxymetazoline, and dexmedetomidine were used to test the role of PGE2in the α2-mediated mechanism that inhibits transport. All agents were added to the bath. Indomethacin at 5 μM significantly elevated CPT-cAMP-stimulated Pf, Jlb, and Pu, and subsequent addition of 100 nM PGE2reduced these transport parameters. Indomethacin reversed α2inhibition of CPT-cAMP-stimulated Pf, Jlb, and Pu, and subsequent addition of PGE2reduced transport in each case. Indomethacin partially reversed α2inhibition of AVP-stimulated Pf, Jlb, and Pu, and PGE2reduced transport back to the α2-inhibited level. These results indicate that PGE2is a second messenger involved in the mechanism of transport inhibition mediated by α2-adrenoceptors via post-cAMP-dependent events in the rat IMCD. |
| Databáze: | OpenAIRE |
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