This Article Résumé de cet Article Full Text Full Text (PDF) Submit a scholarly reply Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Shin, I.-W. Articles by Chung, Y.-K. Search for Related Content PubMed PubMed Citation Articles by Shin, I.-W. Articles by Chung, Y.-K.

Etomidate attenuates phenylephrine-induced contraction in isolated rat aorta

[L’étomidate atténue la contraction induite par la phényléphrine dans des aortes isolées de rats]

Il-Woo Shin, MD^*, Ju-Tae Sohn, MD^*,, Hee-Jin Kim, MD^*, Cheol Kim, MD^*, Heon-Keun Lee, MD^*, Ki Churl Chang, PhD^, and Young-Kyun Chung, MD^*

^* From the Departments of Anesthesia and Pain Medicine, and
Pharmacology, and the Institute of Health Sciences,
Gyeongsang National University College of Medicine, Gyeongnam, Korea.

Address correspondence to: Dr. Ju-Tae Sohn, Department of Anesthesia and Pain Medicine, Gyeongsang National University, Hospital, 90 Chilam-dong, Jinju, Gyeongnam, 660-702, Republic of Korea. Phone: +82-55-750-8586; Fax: + 82-55-750-8142; E-mail: jtsohn{at}nongae.gsnu.ac.kr

Purpose: A previous study has shown that etomidate inhibits the angiotensin II-induced calcium influx in rat aortic smooth muscle cells. The goals of our current in vitro study were to investigate the effect of etomidate on phenylephrine-induced contraction in rat aorta, and to elucidate the associated signalling pathway.

Methods: Endothelium-denuded aortic rings were suspended for isometric tension recording. Concentration-response curves for phenylephrine (10^–9 to 10^–6 M), 5-hydroxytryptamine (10^–7 to 10^–4 M) and potassium chloride (10 to 60 mM) were generated in the presence and absence of etomidate (5 x 10^–6, 3 x 10^–5, 5 x 10^–5 M). For the rings pretreated with verapamil (10^–5 M), the phenylephrine concentration-response curves were generated in the presence and absence of etomidate (5 x 10^–5 M). In the rings exposed to calcium-free isotonic depolarizing solution, the contractile response induced by the addition of calcium was assessed in the presence and absence of etomidate (5 x 10^–5 M).

Results: Etomidate (5 x 10^–5 M) produced a significant rightward shift in the concentration-response curves for phenylephrine, 5-hydroxytryptamine and potassium chloride. Etomidate (5 x 10^–5 M) did not alter phenylephrine-induced contraction in the rings pretreated with verapamil. Etomidate (5 x 10^–5 M) significantly attenuated the contractile response induced by the addition of calcium in the calcium-free isotonic depolarizing solution.

Conclusion: The results suggest that etomidate, which exceeds the clinically relevant concentration, attenuates the phenylephrine-induced contraction by having an inhibitory effect on the calcium influx by blocking the L-type calcium channels in the rat aortic vascular smooth muscle.