Concordant localization of functional urotensin II and urotensin II-related peptide binding sites in the rat brain: Atypical occurrence close to the fourth ventricle

J Comp Neurol. 2014 Aug 1;522(11):2634-49. doi: 10.1002/cne.23553.


Urotensin II (UII) and Urotensin II-related peptide (URP) are structurally related paralog peptides that exert peripheral and central effects. UII binding sites have been partly described in brain, and those of URP have never been reported. We exhaustively compared [(125)I]-UII and -URP binding site distributions in the adult rat brain, and found that they fully overlapped at the regional level. We observed UII/URP binding sites in structures lining ventricles, comprising the sphenoid nucleus and cell rafts scattered on a line joining the fourth ventricle and its lateral recess. After injection of UII and URP in the lateral ventricle, we observed c-Fos-positive cell nuclei in areas close to the fourth ventricle, indicating that these receptors are functional. Different c-Fos-containing cell populations were activated. They were all positive for vimentin and glial fibrillary acidic protein (GFAP), excluding the possibility of an ependymal nature. In conclusion, this study demonstrated that UII and URP binding sites are totally overlapping and that these sites were functional in regions bordering the fourth ventricle. These data support a role for UII/URP at the interface between brain parenchyma and cerebrospinal fluid.

Keywords: CSF; UT receptor; autoradiography; c-Fos; immunohistochemistry; ventricular system.

MeSH terms

  • Animals
  • Autoradiography
  • Binding Sites
  • Brain / metabolism*
  • Fourth Ventricle
  • Glial Fibrillary Acidic Protein / metabolism
  • Immunohistochemistry
  • Iodine Radioisotopes
  • Male
  • Peptide Hormones / metabolism*
  • Proto-Oncogene Proteins c-fos / metabolism
  • Rats, Wistar
  • Urotensins / metabolism*
  • Vimentin / metabolism


  • Glial Fibrillary Acidic Protein
  • Iodine Radioisotopes
  • Peptide Hormones
  • Proto-Oncogene Proteins c-fos
  • Urotensins
  • Vimentin
  • urotensin II-related peptide, rat
  • urotensin II