Inhibitory Effect of Fentanyl on Phenylephrine-Induced Contraction of the Rat Aorta.
10.3349/ymj.2009.50.3.414
- Author:
Kyeong Eon PARK
1
;
Ju Tae SOHN
;
Young Seok JEONG
;
Hui Jin SUNG
;
Il Woo SHIN
;
Heon Keun LEE
;
Young Kyun CHUNG
Author Information
1. Department of Anesthesiology and Pain Medicine, Gyeongsang National University School of Medicine, Jinju, Korea. jtsohn@nongae.gsnu.ac.kr
- Publication Type:Original Article ; In Vitro
- Keywords:
Fentanyl;
phenylephrine;
5-methylurapidil;
BMY 7378;
prazosin;
rat aorta
- MeSH:
Adrenergic alpha-Agonists/*pharmacology;
Adrenergic alpha-Antagonists/*pharmacology;
Animals;
Aorta/*drug effects;
Clonidine/analogs & derivatives/pharmacology;
Fentanyl/*pharmacology;
Male;
Phenylephrine/*pharmacology;
Piperazines/pharmacology;
Rats;
Rats, Sprague-Dawley;
Vasoconstriction/*drug effects
- From:Yonsei Medical Journal
2009;50(3):414-421
- CountryRepublic of Korea
- Language:English
-
Abstract:
PURPOSE: Fentanyl was reported to inhibit the alpha1-adrenoceptor agonist-induced contraction. The goal of this in vitro study was to identify the alpha1-adrenoceptor subtype primarily involved in the fentanyl-induced attenuation of phenylephrine-induced contraction in isolated endothelium-denuded rat aorta. MATERIALS AND METHODS: Aortic rings were suspended in order to record isometric tension. Concentration-response curves for phenylephrine (10-9 to 10-5 M) were generated in the presence or absence of one of the following drugs: fentanyl (3x10-7, 10-6, 3x10-6 M), 5-methylurapidil (3x10-8, 10-7, 3x10-7 M), chloroethylclonidine (10-5 M) and BMY 7378 (3x10-9, 10-8, 3x10-8 M). Phenylephrine concentration-response curves were generated in the presence or absence of fentanyl in rings pretreated with either 3x10-9 M prazosin, 10-9 M 5-methylurapidil or 3x10-9 M BMY 7378. RESULTS: Fentanyl (10-6, 3x10-6 M) attenuated phenylephrine-induced contraction in the rat aorta. 5-Methylurapidil and BMY 7378 produced a parallel rightward shift in the phenylephrine concentration-response curve. The pA2 values for 5-methylurapidil and BMY 7378 were estimated to be 7.71 +/- 0.15 and 8.99 +/- 0.24, respectively. Fentanyl (10-6 M) attenuated phenylephrine-induced contraction in rings pretreated with 10-9 M 5-methylurapidil, but did not alter the rings when pretreated with 3x10-9 M BMY 7378. Pretreatment of the rings with chloroethylclonidine showed a 72.9 +/- 2.3% reduction in phenylephrine-induced maximal contraction. CONCLUSION: The results suggest that fentanyl attenuates phenylephrine-induced contraction by inhibiting the pathway involved in the alpha1D-adrenoceptor-mediated contraction of the rat aorta.
