Korean J Anesthesiol.  2011 Jul;61(1):55-62. 10.4097/kjae.2011.61.1.55.

Indigo carmine enhances phenylephrine-induced contractions in an isolated rat aorta

• Choi YS
• Ok SH
• Lee SM
• Park SS
• Ha YM
• Chang KC
• Kim HJ
• Shin IW
• Sohn JT

• KMID: 2092304
• DOI: http://doi.org/10.4097/kjae.2011.61.1.55

Abstract

BACKGROUND
The intravenous administration of indigo carmine has been reported to produce transiently increased blood pressure in patients. The goal of this in vitro study was to examine the effect of indigo carmine on phenylephrine-induced contractions in an isolated rat aorta and to determine the associated cellular mechanism with particular focus on the endothelium-derived vasodilators.
METHODS
The concentration-response curves for phenylephrine were generated in the presence or absence of indigo carmine. Phenylephrine concentration-response curves were generated for the endothelium-intact rings pretreated independently with a nitric oxide synthase inhibitor, Nomega-nitro-L-arginine methyl ester (L-NAME), a cyclooxygenase inhibitor, indomethacin, and a low-molecular-weight superoxide anion scavenger, tiron, in the presence or absence of indigo carmine. The fluorescence of oxidized dichlorofluorescein was measured in rat aortic vascular smooth muscle cells cultured in the control, indigo carmine alone and tiron plus indigo carmine.
RESULTS
Indigo carmine (10(-5) M) increased the phenylephrine-induced maximum contraction in the endothelium-intact rings with or without indomethacin, whereas indigo carmine produced a slight leftward shift in the phenylephrine concentration-response curves in the endothelium-denuded rings and L-NAME-pretreated endothelium-intact rings. In the endothelium-intact rings pretreated with tiron (10(-2) M), indigo carmine did not alter phenylephrine concentration-response curves significantly. Indigo carmine (10(-5) M) increased the fluorescence of oxidized dichlorofluorescein in the vascular smooth muscle cells, whereas tiron abolished the indigo carmine-induced increase in oxidized dichlorofluorescein fluorescence.
CONCLUSIONS
Indigo carmine increases the phenylephrine-induced contraction mainly through an endothelium-dependent mechanism involving the inactivation of nitric oxide caused by the increased production of reactive oxygen species.

Keyword

Indigo carmine; Nitric oxide; Phenylephrine; Reactive oxygen species

MeSH Terms

1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt
Administration, Intravenous
Animals
Aorta
Blood Pressure
Contracts
Fluorescence
Humans
Indigo Carmine
Indoles
Indomethacin
Muscle, Smooth, Vascular
Nitric Oxide
Nitric Oxide Synthase
Phenylephrine
Prostaglandin-Endoperoxide Synthases
Rats
Reactive Oxygen Species
Superoxides
1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt
Indigo Carmine
Indoles
Indomethacin
Nitric Oxide
Nitric Oxide Synthase
Phenylephrine
Prostaglandin-Endoperoxide Synthases
Reactive Oxygen Species
Superoxides