Endothelium-dependent and -independent vasodilator effects of eugenol in the rat mesenteric vascular bed

Abstract

The possible involvement of the endothelium in the vasodilator action of eugenol was investigated in the mesenteric vascular bed (MVB) of the rat. Bolus injections of eugenol (0.2, 2 and 20 micromol) and acetylcholine (ACh; 10, 30 and 100 pmol) induced dose-dependent vasodilator responses in noradrenaline-precontracted beds that were partially inhibited by pretreatment of the MVB with deoxycholate (1 mg mL(-1)) to remove the endothelium (approximately 14% and approximately 30% of the control response remaining at the lowest doses of ACh and eugenol, respectively). The vasodilator effect of glyceryl trinitrate (1 micromol) was unaltered by deoxycholate. In the presence of either N(omega)-nitro-L-arginine methyl ester (300 microM) or tetraethylammonium (1 mM)the response to ACh was partially reduced, whereas eugenol-induced vasodilation was unaffected. Similarly the vasodilator effect of eugenol was not inhibited by indometacin (3 microM). Under calcium-free conditions the vasoconstrictor response elicited by bolus injections of noradrenaline (10 nmol) was dose-dependently and completely inhibited by eugenol (0.1-1 mM). Additionally, the pressor effects of bolus injections of calcium chloride in potassium-depolarized MVBs were greatly reduced in the presence of eugenol (0.1 mM), with a maximal reduction of approximately 71% of the control response. Our data showed that eugenol induced dose-dependent, reversible vasodilator responses in the rat MVB, that were partially dependent on the endothelium, although apparently independent of nitric oxide, endothelium-derived hyperpolarizing factor or prostacyclin. Furthermore, an endothelium-independent intracellular site of action seemed likely to participate in its smooth muscle relaxant properties.

Eugenol dilates mesenteric arteries and reduces systemic BP by activating endothelial cell TRPV4 channels

“…Our data indicate that eugenol-induced relaxation in mesenteric arteries is mediated, in part, via the endothelium. These results agree with previous studies demonstrating that eugenol-induced vasorelaxation is partially dependent on the endothelium in rat aorta, a conduit vessel, and a whole mesentery preparation (Criddle et al, 2003;Damiani et al, 2003). Eugenol also relaxed endothelium-denuded arteries.…”

“…Eugenol also relaxed rat aorta and an intact mesenteric bed. The effects were shown to be partially dependent on the endothelium, but their mechanisms of action were unclear (Criddle et al, 2003;Damiani et al, 2003).…”

Effects of anethole and structural analogues on the contractility of rat isolated aorta: Involvement of voltage-dependent Ca2+-channels

“…In the present study the relaxant action of anethole was also independent of nitric oxide production since it was not inhibited by L-NAME, a nitric oxide synthase blocker (Rees et al, 1989) suggesting a similar profile of action to eugenol. In agreement, we have previously shown that eugenol evoked vasodilation of perfused mesenteric resistance vessels that was partially endotheliumdependent, although apparently independent of nitric oxide, endothelium-derived hyperpolarizing factor or prostacyclin production (Criddle et al, 2003). In a similar manner, the effects of anethole on the rat isolated aorta were not inhibited by indomethacin, ruling out possible involvement of prostaglandins.…”

“…Its structural analogue eugenol (4-allyl-2-methoxyphenol), also a major constituent of medicinal plant essential oils, has been more extensively characterized in blood vessels. For example, we have previously demonstrated both endothelium-dependent and -independent vasodilator effects of eugenol in rat perfused mesenteric Life Sciences 81 (2007) 1085 -1093 www.elsevier.com/locate/lifescie resistance arteries (Criddle et al, 2003), whilst contractile studies in isolated blood vessels have indicated a modulatory effect of the endothelium on eugenol-induced vasorelaxation (Nishijima et al, 1998;Damiani et al, 2003). Therefore the aim of the present study was to compare the actions of anethole and its isomer estragole, with those of eugenol and isoeugenol (Fig.…”

Tumor Exosomes Inhibit Differentiation of Bone Marrow Dendritic Cells

“…BM-derived DC were generated from primary cultures of femoral marrow from 6-to 8-wk-old female wild-type (WT) and IL-6 Ϫ/Ϫ mice as described previously (18). In brief, BM cells were flushed from the femurs of 6-to 8-wk-old mice using an RPMI 1640-filled syringe to obtain a single-cell suspension.…”