Ionic radiocontrast inhibits endothelium-dependent vasodilation of the canine renal artery in vitro: Possible mechanism of renal failure following contrast medium infusion

B. Discigil, P. R.B. Evora, P. J. Pearson, F. Viaro, A. J. Rodrigues, H. V. Schaff

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

To determine if radiocontrast impairs vascular relaxation of the renal artery, segments (4-5 mm in length) of canine renal artery were suspended in vitro in organ chambers to measure isometric force (95% O2/5% CO2, at 37°C). Arterial segments with and without endothelium were placed at the optimal point of their length-tension relation and incubated with 10 μM indomethacin to prevent synthesis of endogenous prostanoids. The presence of nonionic radiocontrast (iohexol, Omnipaque 350, 1 ml in 25 ml control solution, 4% (v/v)) did not alter endothelium-dependent relaxation to acetylcholine in rings precontracted with both norepinephrine and prostaglandin F (N = 6). When the rings were precontracted with prostaglandin F, the presence of ionic contrast did not inhibit the relaxation of the arteries. However, in canine renal arteries contracted with norepinephrine, the presence of ionic radiocontrast (diatrizoate meglumine and diatrizoate sodium, MD-76, 1 ml in 25 ml control solution, 4% (v/v)) inhibited relaxation in response to acetylcholine, sodium nitroprusside (N = 6 in each group), and isoproterenol (N = 5; P < 0.05). Rings were relaxed less than 50% of norepinephrine contraction. Following removal of the contrast, vascular relaxation in response to the agonists returned to normal. These results indicate that ionic radiocontrast nonspecifically inhibits vasodilation (both cAMP-mediated and cGMP-mediated) of canine renal arteries contracted with norepinephrine. This reversible impairment of vasodilation could inhibit normal renal perfusion and act as a mechanism of renal failure following radiocontrast infusion. In the adopted experimental protocol the isoproterenol-induced relaxation of renal arteries precontracted with norepinephrine was more affected, suggesting a pivotal role of the cAMP system.

Original languageEnglish (US)
Pages (from-to)259-265
Number of pages7
JournalBrazilian Journal of Medical and Biological Research
Volume37
Issue number2
DOIs
StatePublished - Feb 2004

Keywords

  • Nitric oxide
  • Radiocontrast
  • Renal failure
  • Vasodilation

ASJC Scopus subject areas

  • Biophysics
  • Neuroscience(all)
  • Biochemistry
  • Physiology
  • Immunology
  • Pharmacology, Toxicology and Pharmaceutics(all)
  • Cell Biology

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