Korean J Anesthesiol.  2000 Sep;39(3):411-416. 10.4097/kjae.2000.39.3.411.

The Effects of Etomidate on the Isolated Porcine Coronary Artery

• Suh JK
• Shin WJ
• Yeom JH
• Cho SY
• Jun JH
• Kim KH
• Shim JC

• KMID: 2237608
• DOI: http://doi.org/10.4097/kjae.2000.39.3.411

Abstract

BACKGROUND: Etomidate produces minimal cardiovascular effects in clinical uses but their effects on the porcine coronary arteries are not well known yet. We studied the direct effects of etomidate on porcine coronary arterial tone and the underlying mechanism of its vascular relaxation.
METHODS
Porcine coronary arterial ring segments (3-4 mm) with or without endothelium were suspended in modified Krebs solution (37oC) and preconstricted with K+ 40 mM. Changes in tension were measured following cumulative administrations of etomidate (10(-5), 5 x 10(-5) and 10(-4) M). Relaxation caused by etomidate (10(-4)M) were measured in the presence of either NG-nitro-L-arginine methyl ether (L-NAME 10(-5)M, n = 13), indomethacin (2.8 x 10(-5)M, n = 12), methylene blue (2 x 10(-5)M, n = 12), tetraethylammonium (TEA, KCa2+ blocker, 20 mM, n = 11), glibenclamide (n = 13) 2.5 x 10(-5)M or 4-aminopyridine (4-AP, K+ DR blocker, 10 4 M, n = 12). Effects of etomidate on Ca2+ influx through the voltage operated channel (VOC) of the vascular cells were also evaluated.
RESULTS
Arterial reings were relaxed by etomidate in a concentration-dependent manner and these effects were not affected by endothelium. In the etomidate pretreated group, arterial ring in a calcium-free solution showed no contraction with KCl 40 mM, but the contraction after the administration of calcium 2.5 mM less than without etomidate group (47.2 +/- 8.7% vs 97.7 +/- 10.6%). The other group, not pretreated with etomidate, showed the same vascular tone of the control group in a slow upstroke manner with calcium administration. Pretreatment with either L-NAME, indomethacin and methylene blue did not affect etomidate-induced vasorelaxation. The TEA, glibenclamide and 4-AP pretreated groups also did not affect the vascular relaxation.
CONCLUSIONS
Etomidate relaxes the porcine coronary artery in a concentration-dependent manner withor without endothelium, via inhibition of Ca2+ influx through the voltage-operated Ca2+ channel.

Keyword

Anesthetics, intravenous: etomidate; Artery: porcine coronary artery; endothelium; Ion channel: Ca2+ channel; K+ channel; Pharmacology: L-NAME; indomethacin; methylene blue; tetraethyl ammonium; glibenclamide; 4-aminopyridine

MeSH Terms

4-Aminopyridine
Calcium
Coronary Vessels*
Endothelium
Ether
Etomidate*
Glyburide
Indomethacin
Methylene Blue
NG-Nitroarginine Methyl Ester
Nitroarginine
Relaxation
Tea
Tetraethylammonium
Vasodilation
4-Aminopyridine
Calcium
Ether
Etomidate
Glyburide
Indomethacin
Methylene Blue
NG-Nitroarginine Methyl Ester
Nitroarginine
Tea
Tetraethylammonium