Functional receptors for fish neuropeptide urotensin II in major rat arteries

Eur J Pharmacol. 1988 Apr 27;149(1-2):61-6. doi: 10.1016/0014-2999(88)90042-8.


Receptor binding of fish neuropeptide urotensin II (UII) was characterized in membranes isolated from major rat arteries. Monoiodinated UII radioligand (125I-UII) was prepared and purified using high-pressure liquid chromatography (HPLC). The contractile potency of iodinated UII (I-UII) on rat thoracic aorta strips was somewhat lower than that of native UII. The binding of 125I-UII to the membrane preparations of rat thoracic aorta was saturable, specific and time-dependent. Scatchard analysis indicated a single population of binding sites with an apparent dissociation constant of 5.9 x 10(-9) M. The calculated maximal number of binding sites was about 155 fmol/mg protein. The specific binding to the membrane preparations from the abdominal aorta and mesenteric artery was about 27 and 8%, respectively, of those in the thoracic aorta, which corresponds to the order of contractile potency of UII on rat blood vessels: thoracic aorta greater than abdominal aorta greater than mesenteric artery. The displacement of 125I-UII binding by the UII peptide or its fragments (UII-(5-12), UII-(6-12) and UII-(6-11] were also comparable to their contractile effects on rat thoracic aorta strips (UII greater than UII-(5-12) greater than UII-(6-12) much greater than UII-(6-11]. These results suggest that the fish neuropeptide, UII, can induce contraction of rat vascular tissue by interacting with its functional receptors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aorta, Thoracic / metabolism
  • Arteries / metabolism
  • Binding Sites
  • Fishes / metabolism*
  • In Vitro Techniques
  • Indicators and Reagents
  • Iodine Radioisotopes
  • Male
  • Muscle Contraction / drug effects
  • Muscle, Smooth, Vascular / metabolism*
  • Peptides / metabolism*
  • Rats
  • Rats, Inbred Strains
  • Urotensins / metabolism*


  • Indicators and Reagents
  • Iodine Radioisotopes
  • Peptides
  • Urotensins
  • urotensin II