Autoradiographic localization of dopamine DA1 receptors in rat kidney with ( sup 3 H)Sch 23390
- City Univ. of New York, NY (USA)
Dopamine receptors in the rat kidney were characterized by homogenate binding and in vitro autoradiography using the dopamine 1 (DA1)-selective antagonist ({sup 3}H)Sch 23390. ({sup 3}H)Sch 23390 binding in cortical membrane preparations was saturable, stereoselective, and competed for by DA agonists and antagonists with a rank order of potency consistent with the labeling of the DA1 receptor. ({sup 3}H)Sch 22390 binding was best fit to a two-site model: a high affinity-low density site (KD1 4.9 +/- 1.4 nM, Bmax 1 31.4 +/- 13.8 fmol/mg protein) and a low affinity-high density site (KD2 86.4 +/- 23.9 nM, Bmax 2 848.0 +/- 227.4 fmol/mg protein). In vitro autoradiography indicated that ({sup 3}H)Sch 22390 binding sites were restricted to the cortex. High-resolution autoradiography further indicated that ({sup 3}H)Sch 22390 binding sites were localized primarily on proximal tubules. Glomeruli and other vascular elements were devoid of ({sup 3}H)Sch 23390 binding sites. These results suggest that DA and DA1 agonists may affect sodium excretion by a direct action on proximal tubule sodium reabsorption.
- OSTI ID:
- 5412690
- Journal Information:
- American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 257; ISSN 0002-9513; ISSN AJPHA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
AMINES
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
AUTORADIOGRAPHY
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL LOCALIZATION
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL COMPOSITION
DISTRIBUTION
DOPAMINE
DRUGS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
KIDNEYS
KINETICS
MAMMALS
MATHEMATICAL MODELS
MEMBRANE PROTEINS
MEMBRANES
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANS
PHENOLS
POLYPHENOLS
PROTEINS
RATS
REACTION KINETICS
RECEPTORS
RODENTS
SYMPATHOMIMETICS
TISSUE DISTRIBUTION
TRITIUM COMPOUNDS
VERTEBRATES