Vasodilatory effects of cinnamic acid via the nitric oxide-cGMP-PKG pathway in rat thoracic aorta.

Cinnamic acid (CA) and its derivatives have a broad therapeutic spectrum that includes antimicrobial, antifungal, and antitumoral activities. However, the vasodilative effect of CA has not been demonstrated. The present study characterizes the vasodilative activity and the mechanism of CA in rat thoracic aorta. The vasomotion of aortic strips following CA treatment was measured in an organ bath system. In addition, vascular strips and human umbilical vein endothelial cells (HUVECs) were used in organ bath, Western blot, nitrite, and cyclic guanosine monophosphate (cGMP) measurements. CA relaxed phenylephrine-precontracted aortic strips in an endothelium-dependent manner. Pretreatment of the endothelium-intact aortic strips with N(G) -nitro-l-arginine methyl ester (10(-4)  M), 1 H-[1,2,4]-oxadiazolole-[4,3-a] quinoxalin-10-one, (10(-6)  M) and methylene blue (10(-5)  M) inhibited CA-induced vasorelaxation. CA also increased the phosphorylation of endothelial nitric oxide synthase and nitric oxide generation in a concentration-dependent manner in HUVECs. In addition, cGMP generation and cGMP-dependent protein kinase G (PKG) expression in aortic strips were increased by CA treatment. Furthermore, CA-induced vasorelaxation was inhibited by the PKG inhibitor KT5823 (0.3 μM) and the Ca(2+) -activated K(+) channel inhibitor tetraethylammonium (10(-3)  M). These findings suggest that CA exerts an endothelium-dependent vasodilation effect via the nitric oxide-cGMP-PKG-mediated pathway in rat thoracic aorta.

Kang YH ，Kang JS ，Shin HM 《-》

Cinnamyl alcohol attenuates vasoconstriction by activation of K⁺ channels via NO-cGMP-protein kinase G pathway and inhibition of Rho-kinase.

Kang YH ，Yang IJ ，Morgan KG ，Shin HM ... -  《-》

Vasodilatory effect of kaempferol-7-O-α-L-rhamnopyranoside via NO-cGMP-PKG signaling.

Hypertension is one of the major causes of mortality. Though a host of drugs are available for the treatment of hypertension, majority have been linked to adverse side effects, necessitating the need for research into natural compounds with fewer side effects. Kaempferol-7-O-α-L-rhamnopyroside (KR) is a glycosylated flavone with neuroprotective and anti-inflammatory effects. However, no available literature exists on its vasodilatory effect. This study examined the pharmacological effect of KR on vasodilation/vasorelaxation and its mechanism of action in endothelial cells and rat thoracic aorta. Treatment of phenylephrine (PE; 2 × 10-6 M)-pre-contracted aortic rings with KR induced endothelium-dependent relaxation, which was suppressed by NG-nitro-l-arginine methyl ester (L-NAME; 10-4 M), (nitric oxide synthase (NOS) inhibitor). Phosphorylation of eNOS in human umbilical vein endothelial cells (HUVECs) was increased after exposure to KR. Pre-treatment of aortic rings with the cyclic GMP (cGMP) inhibitors; methylene blue (MB; 10-5 M) and 1-H-[1,2,4]-oxadiazolole-[4,3-α]-quinoxalin-10-one, (ODQ; 10-6 M) suppressed the KR-induced vasodilation. Furthermore, KR also increased protein kinase G (PKG) levels whereas it suppressed levels of phosphorylated myosin light chain (MLC) and protein kinase C (PKC) in aortic rings. These results suggest that KR induces endothelium-dependent vasorelaxation via the NO-cGMP-PKG pathway.

Tettey CO ，Yang IJ ，Shin HM 《-》

Mantidis ootheca induces vascular relaxation through PI3K/AKT-mediated nitric oxide-cyclic GMP-protein kinase G signaling in endothelial cells.

Kim HY ，Lee YJ ，Han BH ，Yoon JJ ，Ahn YM ，Hong MH ，Tan R ，Kang DG ，Lee HS ... -  《-》

Polygonum viviparum L. induces vasorelaxation in the rat thoracic aorta via activation of nitric oxide synthase in endothelial cells.

Chang ML ，Chang JS ，Yu WY ，Cheah KP ，Li JS ，Cheng HW ，Hu CM ... -  《BMC Complementary and Alternative Medicine》