Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

These studies were conducted to determine whether the alpha 2-agonists epinephrine and dexmedetomidine inhibit osmotic water permeability (Pf) and urea permeability (Pu) in the rat inner medullary collecting duct (IMCD). Wistar rat IMCD segments were perfused via standard methods, and Pf and Pu were determined in separate studies. The control period was followed by adding 220 pM arginine vasopressin (AVP) or 10(-4) M dibutyryladenosine 3',5'-cyclic monophosphate (DBcAMP) to the bath. Epinephrine or dexmedetomidine, both at 1 microM, was then added to the bath, and this period was followed by adding 1 microM atipamezole, a selective alpha 2-antagonist. The phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine was present in all experiments with DBcAMP. Epinephrine inhibited AVP- and DBcAMP-stimulated Pf by 90% and 80%, respectively. Dexmedetomidine inhibited AVP- and DBcAMP-stimulated Pf by 98% and 97%, respectively. Epinephrine inhibited AVP- and DBcAMP-stimulated Pu by 70% and 60%, respectively. Dexmedetomidine failed to affect Pu. Atipamezole reversed all inhibitory effects. These data confirm an alpha 2-mediated mechanism in the IMCD that modulates Pf and Pu, and they indicate that inhibition occurs via post-cAMP cellular events.
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PMID:Alpha 2-adrenergic-mediated inhibition of water and urea permeability in the rat IMCD. 876 Feb 56

The purpose of this study was to determine whether the selective alpha-2 agonist dexmedetomidine inhibits basic transport properties in the rat cortical collecting duct (CCD). Sprague-Dawley rat CCDs were isolated and perfused to allow measurement of osmotic water permeability (Pf), transepithelial voltage (Vt) and resistance (Rt). Arginine vasopressin (AVP) increases Pf, hyperpolarizes Vt and decreases Rt in the CCD via stimulation of adenylyl cyclase. Dexmedetomidine at 100 nM added to the basolateral side of the CCD reduced AVP-stimulated Pf by 95% to 100%, and the alpha-2 antagonist atipamezole reversed the inhibition. In the presence of the protein kinase C inhibitor staurosporine, dexmedetomidine reduced AVP-stimulated Pf by 70% to 75% compared with the complete inhibition without staurosporine. When Pf was increased by the use of the non-hydrolyzable analog of cAMP, 8-chlorophenylthio-cAMP, in lieu of AVP, dexmedetomidine inhibited Pf by approximately 35%. This demonstrated alpha-2-mediated inhibition of Pf despite the presence of constant cellular cAMP levels. Dexmedetomidine reversed AVP-induced effects on Vt and Rt, indicating inhibition of Na+ transport. Results confirm an alpha-2-mediated mechanism that reduces Na+ and water transport in the CCD and suggest that a cellular messenger other than cAMP is involved. This messenger could be protein kinase C.
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PMID:Dexmedetomidine inhibits osmotic water permeability in the rat cortical collecting duct. 910 81

These studies were conducted to determine if the prostaglandin-synthesis inhibitor indomethacin or the protein kinase C (PKC) inhibitor staurosporine affect the inhibition of osmotic water permeability (Pf) by the alpha-2 (alpha 2) agonist dexmedetomidine in the rat inner medullary collecting duct (IMCD). Terminal IMCDs from Wistar rats were perfused and Pf was increased with either 220 pM arginine vasopressin (AVP) or 0.1 mM 8-chlorophenylthio cyclic adenosine monophosphate (8CPTcAMP). All agents were added to the bathing solution. Dexmedetomidine at 100 nM inhibited both AVP- and 8CPTcAMP-stimulated Pf. When Pf was increased by AVP, indomethacin at 0.1 mM or 5 microM reversed the dexmedetomidine-induced inhibition by 68% and 43%, respectively. When Pf was increased by 8CPTcAMP, indomethacin at 0.1 mM or 5 microM reversed inhibition by 83% and 70%, respectively. Indomethacin increased AVP and 8CPTcAMP-stimulated Pf by 20 to 30% and dexmedetomidine inhibited the AVP+ indomethacin-stimulated Pf. Staurosporine at 10 nM yielded similar results. Results suggest that PKC and prostaglandins are involved in the alpha 2 mediated mechanism, and staurosporine and indomethacin-sensitive cellular mediators modulate basal Pf.
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PMID:Indomethacin and staurosporine reverse alpha 2 inhibition of water transport in rat IMCD. 935 Jun 58