title: Differential modulation of the renal proximal tubular DA-1 receptor by Gpp(NH)p and sodium in the spontaneously hypertensive rat.
abstract: 1. In the normotensive rat (WKY) the guanine nucleotide, Gpp(NH)p, and sodium reduced the ability of the dopaminergic agonist fenoldopam to compete for the [3H]-SKF-38393 (dopamine-1 agonist) binding to the renal proximal tubular DA-1 receptors. 2. In the spontaneously hypertensive rat (SHR) Gpp(NH)p failed to reduce the affinity of fenoldopam for [3H]-SKF-38393 binding to renal tubular DA-1 receptors. 3. Sodium reduced the affinity of fenoldopam for [3H]-SKF-38393 binding in the SHR renal proximal tubular cells, but to a lesser extent than the WKY. 4. We conclude that the SHR has a defective DA-1 receptor or Gs/receptor coupling which interferes with the ability of Gpp(NH)p to act on the DA receptor/G protein complex.
authors.affiliation: Department of Pathology, University of Virginia Health Sciences Center, Charlottesville 22908.
authors.forename: R A
authors.initials: RA
authors.lastname: Felder
authors.forename: M
authors.initials: M
authors.lastname: VanCampen
mesh_terms: D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000031:analogs & derivatives / Q000378:metabolism; D000818:Animals; D015259:Dopamine Agents / Q000378:metabolism; D018818:Fenoldopam; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D006973:Hypertension / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D011954:Receptors, Dopamine / Q000187:drug effects / Q000378:metabolism*; D017447:Receptors, Dopamine D1; D012964:Sodium / Q000494:pharmacology
chemical_list: D015259:Dopamine Agents; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D006165:Guanylyl Imidodiphosphate; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D012964:Sodium; D018818:Fenoldopam