title: Overexpression of histamine H₄ receptors in the kidney of diabetic rat.
abstract: OBJECTIVE
  The renal expression of H1 and H2 receptors has previously been demonstrated, while that of the H4 receptor has been poorly investigated, and thus the aim of this research was to investigate the expression of the H4 receptor in the kidney of diabetic rats.
  
  
  METHODS
  24 8-week-old male Wistar rats.
  
  
  METHODS
  Diabetes was induced in 12 rats by a single intravenous injection of streptozotocin, and animals were killed 6 weeks later.
  
  
  METHODS
  Kidneys were collected and processed for quantitative PCR or immunohistochemical analyses. To ascertain the renal topology of the H4 receptor, colocalization experiments were performed with a series of markers.
  
  
  RESULTS
  H4 receptor is expressed in healthy rats, although at a very low level, and is strongly upregulated in diabetic animals. Immunohistochemical analysis revealed the highest immune-positivity in the medulla. Colocalization experiments revealed a close overlap in expression topology of the H4 receptor and both Tamm-Horsfall glycoprotein and aquaporin 1 was observed.
  
  
  CONCLUSIONS
  The results demonstrate, for the first time, that the H4 receptor is expressed in the kidney mainly by resident renal cells of the loop of Henlé and that this receptor is significantly overexpressed in diabetic animals, thus suggesting a possible role in the pathogenesis of diabetes-associated renal disease.
authors.affiliation: Dipartmento di Scienza e Tecnologia del Farmaco, Università di Torino, Turin, Italy. ariannacarolina.rosa@unito.it
authors.forename: A C
authors.initials: AC
authors.lastname: Rosa
authors.forename: C
authors.initials: C
authors.lastname: Grange
authors.forename: A
authors.initials: A
authors.lastname: Pini
authors.forename: M A
authors.initials: MA
authors.lastname: Katebe
authors.forename: E
authors.initials: E
authors.lastname: Benetti
authors.forename: M
authors.initials: M
authors.lastname: Collino
authors.forename: G
authors.initials: G
authors.lastname: Miglio
authors.forename: D
authors.initials: D
authors.lastname: Bani
authors.forename: G
authors.initials: G
authors.lastname: Camussi
authors.forename: P L
authors.initials: PL
authors.lastname: Chazot
authors.forename: R
authors.initials: R
authors.lastname: Fantozzi
mesh_terms: D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism* / Q000473:pathology; D006943:Hyperglycemia / Q000378:metabolism* / Q000473:pathology; D007668:Kidney / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D011968:Receptors, Histamine / Q000378:metabolism*; D000074040:Receptors, Histamine H4
chemical_list: C498828:Hrh4 protein, rat; D043562:Receptors, G-Protein-Coupled; D011968:Receptors, Histamine; D000074040:Receptors, Histamine H4