title: Differential expression of D2-like dopamine receptors in the kidney of the spontaneously hypertensive rat.
abstract: OBJECTIVE
  To compare the expression and cellular distribution of D(2)-like dopamine receptors in the kidney of the spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto (WKY) rat.
  
  
  METHODS
  Renal D(2)-like receptor protein expression and distribution has not been studied in the SHR. Since changes in D(2)-like receptor expression and/or distribution may contribute to the dysregulation of renal dopamine and D(1A) receptor function, we examined the expression of the three subtypes of D(2)-like receptors (D(2), D(3) and D(4)) in SHR and WKY rat kidneys.
  
  
  METHODS
  Western blot analysis and confocal immunocytochemistry with specific polyclonal antipeptide antibodies directed against the receptor subtypes, were used to assess protein expression.
  
  
  RESULTS
  There were no differences in protein expression and cellular immunolocalization of the D(2) receptor subtypes between SHR and WKY rats. Expression of the 50 kDa D(3) receptor was reduced in the cortex of the SHR; no differences in D(3) receptor levels were seen in the inner medulla of SHR and WKY rats. The D(4) receptor polypeptides were overexpressed in the cortex of SHR, while in the inner medulla no difference in expression of the D(4) receptor proteins was observed between SHR and WKY rats. Immunocytochemistry also showed increased immunostaining of D(4) receptors in tubular structures in the cortex, but diminished staining in the SHR inner medulla.
  
  
  CONCLUSIONS
  The observed differences in expression and distribution of D(3) and D(4) dopamine receptors between cortex and inner medulla of the kidneys of SHR and WKY rats may contribute to the aberrant state of dopaminergic-mediated natriuresis in SHR.
authors.affiliation: Department of Pediatrics, Georgetown University Medical Center, 3970 Reservoir Road NW, Washington, DC 20007, USA.
authors.forename: Yangmee
authors.initials: Y
authors.lastname: Shin
authors.forename: Ujendra
authors.initials: U
authors.lastname: Kumar
authors.forename: Yogesh
authors.initials: Y
authors.lastname: Patel
authors.forename: Shutish C
authors.initials: SC
authors.lastname: Patel
authors.forename: Anita
authors.initials: A
authors.lastname: Sidhu
mesh_terms: D000818:Animals; D015153:Blotting, Western; D006973:Hypertension / Q000378:metabolism*; D007150:Immunohistochemistry; D007668:Kidney / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D050637:Receptors, Dopamine D3; D050638:Receptors, Dopamine D4; D014018:Tissue Distribution
chemical_list: C493595:Drd3 protein, rat; C493601:Drd4 protein, rat; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D050638:Receptors, Dopamine D4