TITLE:
Inhibitory Effect of Fentanyl on Phenylephrine-Induced Contraction on Rabbit Aorta
AUTHORS:
Sevda Sasmaz, Ayse Saide Sahin, Ipek Duman
KEYWORDS:
Fentanyl, Nitric Oxide, Potassium Channels, Rabbit, Vascular Smooth Muscle
JOURNAL NAME:
Pharmacology & Pharmacy,
Vol.2 No.3,
July
28,
2011
ABSTRACT: This in vitro study was designed to assess the effects of fentanyl on isolated rabbit thoracic aorta rings contracted with phenylephrine. Methods included contraction of aorta rings with phenylephrine (10–5 M) and recording the changes after increasing concentrations of fentanyl (10–9 M – 10–5 M). Similar experiments were done after incubation with Nω- nitro-L-arginine methyl ester (10–4 M), indomethacin (10-5 M), naloxone (10–5 M), ouabain (10–5 M), TEA (10–4 M) and glibenclamide (10–5 M). It was revealed that, fentanyl causes relaxation in rabbit aorta rings precontracted with phenylephrine. Removal of endothelium significantly reduces the relaxant response to fentanyl. Nitric oxide synthase inhibitor L-NAME, K+ channel blocker glibenclamide and Na+/K+ ATPase inhibitor ouabain inhibits the relaxant effect of fentanyl in endothelium intact aorta rings. These results suggest that fentanyl causes dose dependent vasodilatation in the rabbit aorta via activation of KATP channels and Na+-K+ -ATPase, and nitric oxide released from endothelium.