title: The cooperative roles of the dopamine receptors, D1R and D5R, on the regulation of renal sodium transport.
abstract: Determining the individual roles of the two dopamine D1-like receptors (D1R and D5R) on sodium transport in the human renal proximal tubule has been complicated by their structural and functional similarity. Here we used a novel D5R-selective antagonist (LE-PM436) and D1R- or D5R-specific gene silencing to determine second messenger coupling pathways and heterologous receptor interaction between the two receptors. D1R and D5R colocalize in renal proximal tubule cells and physically interact, as determined by co-immunoprecipitation and fluorescent resonance energy transfer microscopy. Stimulation of renal proximal tubule cells with fenoldopam (D1R/D5R agonist) led to both adenylyl cyclase and phospholipase C (PLC) activation using real-time fluorescent resonance energy transfer biosensors ICUE3 and CYPHR, respectively. Fenoldopam increased cAMP accumulation and PLC activity and inhibited both NHE3 and NaKATPase activities. LE-PM436 and D5R siRNA blocked the fenoldopam-stimulated PLC pathway but not cAMP accumulation, whereas D1R siRNA blocked both fenoldopam-stimulated cAMP accumulation and PLC signaling. Either D1R or D5R siRNA, or LE-PM436 blocked the fenoldopam-dependent inhibition of sodium transport. Further studies using the cAMP-selective D1R/D5R agonist SKF83822 and PLC-selective D1R/D5R agonist SKF83959 confirmed the cooperative influence of the two pathways on sodium transport. Thus, D1R and D5R interact in the inhibition of NHE3 and NaKATPase activity, the D1R primarily by cAMP, whereas the D1R/D5R heteromer modulates the D1R effect through a PLC pathway.
authors.affiliation: The University of Virginia Health System, Department of Pathology, Charlottesville, Virginia, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Gildea
authors.affiliation: The University of Virginia Health System, Department of Pathology, Charlottesville, Virginia, USA.
authors.forename: Ishan T
authors.initials: IT
authors.lastname: Shah
authors.affiliation: The University of Virginia Health System, Department of Pathology, Charlottesville, Virginia, USA.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Van Sciver
authors.affiliation: The University of Virginia Health System, Department of Pathology, Charlottesville, Virginia, USA.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Israel
authors.affiliation: Institut für Pharmazie, Lehrstuhl für Pharmazeutische/Medizinische Chemie, Friedrich-Schiller-Universität Jena, Jena, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Enzensperger
authors.affiliation: The University of Virginia Health System, Department of Pathology, Charlottesville, Virginia, USA.
authors.forename: Helen E
authors.initials: HE
authors.lastname: McGrath
authors.affiliation: University of Maryland School of Medicine, Departments of Medicine and Physiology, Baltimore, Maryland, USA.
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Jose
authors.affiliation: The University of Virginia Health System, Department of Pathology, Charlottesville, Virginia, USA.
authors.forename: Robin A
authors.initials: RA
authors.lastname: Felder
mesh_terms: D001552:Benzazepines / Q000494:pharmacology; D001693:Biological Transport, Active / Q000187:drug effects; D002478:Cells, Cultured; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D018818:Fenoldopam / Q000494:pharmacology; D031541:Fluorescence Resonance Energy Transfer; D057809:HEK293 Cells; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism*; D008954:Models, Biological; D034741:RNA, Small Interfering / Q000235:genetics; D017447:Receptors, Dopamine D1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D050641:Receptors, Dopamine D5 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015290:Second Messenger Systems; D012964:Sodium / Q000378:metabolism*
chemical_list: C494644:3-allyl-6-chloro-7,8-dihydroxy-1-(3-methylphenyl)-2,3,4,5-tetrahydro-1H-3-benzazepine; D001552:Benzazepines; D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D034741:RNA, Small Interfering; D017447:Receptors, Dopamine D1; D050641:Receptors, Dopamine D5; D012964:Sodium; D018818:Fenoldopam