Inhibitory Effect of Fentanyl on Phenylephrine-Induced Contraction of the Rat Aorta
Yonsei Medical Journal
; : 414-421, 2009.
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| ID: wpr-110993
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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.
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Texto completo:
1
Índice:
WPRIM
Assunto principal:
Aorta
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Fenilefrina
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Piperazinas
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Vasoconstrição
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Fentanila
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Clonidina
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Ratos Sprague-Dawley
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Agonistas alfa-Adrenérgicos
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Antagonistas Adrenérgicos alfa
Limite:
Animals
Idioma:
En
Revista:
Yonsei Medical Journal
Ano de publicação:
2009
Tipo de documento:
Article