Friday, April 10, 2009

Propolis Component Relaxes Coronary Artery Ring Segments

The Vasorelaxant Effect of Caffeic Acid Phenethyl Ester on Porcine Coronary Artery Ring Segments
Vascular Pharmacology, Article in Press

Caffeic acid phenethyl ester (CAPE) is a naturally occurring compound isolated from honeybee propolis whose cardiovascular properties remain uncertain. The purpose of this study was to investigate the possible mechanisms of CAPE-induced vasorelaxation in porcine coronary artery rings.

It was found that both the quiescent and pre-contracted coronary artery ring segments were relaxed by CAPE (10- 7 ~ 10- 4 M). Nω-nitro-L-arginine (L-NNA), methylene blue and removal of endothelium significantly attenuated CAPE-induced relaxation of both quiescent and pre-contracted artery rings. This relaxing effect of CAPE on coronary arteries was also significantly reduced by propranolol, and SQ22536, but not by indomethacin. In addition, the dose-response curves of KCl (2.5 ~ 100 mM) and CaCl2 (10- 5 ~ 10- 2 M) were displaced downwards in the presence of CAPE.

These results suggest that the relaxant effect of CAPE on porcine coronary artery rings might involve the action of nitric oxide (NO) and adrenergic β-receptor, together with their second messenger, cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP), respectively, but not involve the synthesis of prostaglandin.

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