Supplementary Material for: Pharmacological Characteristics of the Inhibitory Effects of Docosahexaenoic Acid on Vascular Contractions Studied in Rat Mesenteric Artery

<b><i>Background/Aims:</i></b> Effects of docosahexaenoic acid (DHA) on blood vessel contractions to various constrictors were investigated in rat mesenteric artery and compared with those of eicosapentaenoic acid (EPA) and linoleic acid (LA). <b><i>Methods:</i></b> Tension changes in mesenteric ring segments were isometrically recorded. <b><i>Results:</i></b> On sustained contractions induced by a thromboxane A<sub>2</sub> mimetic (U46619), DHA exerted a strong inhibitory effect. This inhibitory effect of DHA on U46619 appeared both in endothelium-intact and endothelium-denuded preparations. Although the inhibitory effect of DHA on prostaglandin F<sub>2α</sub> (PGF<sub>2α</sub>)-induced contractions was also significant, contractions to phenylephrine (PE) and high-KCI were not affected by DHA. As well as DHA, EPA strongly diminished U46619- and PGF<sub>2α</sub>-induced contractions without showing a substantial inhibition of PE- and high-KCl-induced contractions. By contrast, LA did not show any significant inhibitory effects on any contractions. The DHA-induced inhibitory actions exerted on U46619 and PGF<sub>2α</sub> also emerged if ring preparations were pretreated with this ω-3 polyunsaturated fatty acid (PUFA). <b><i>Conclusion:</i></b> DHA and EPA are found to more pronouncedly inhibit prostanoid receptor-mediated contractions than other constrictor responses of the mesenteric artery via endothelium-independent mechanisms. These inhibitory effects of ω-3 PUFAs on prostanoid receptor-mediated contractions may partly underlie the mechanisms by which these ω-3 PUFAs elicit protective actions against circulatory disorders.