system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Animals, Catechin, Endothelium, Vascular, In Vitro Techniques, Male, Mesenteric Arteries, Methylene Blue, Muscle, Smooth, Vascular, NG-Nitroarginine Methyl Ester, Nitric Oxide Synthase, Phenylephrine, Rats, Rats, Sprague-Dawley, Stereoisomerism, Tea, Vasodilation.
user
Does ( - ) epicatechin induce and modulates endothelium-dependent relaxation in isolated rat mesenteric artery rings? Context: The present study was aimed to examine the role of endothelial nitric oxide in the relaxant response to green tea (-)epicatechin and its modulation of endothelium-mediated relaxation in the isolated rat mesenteric artery rings. Changes in the isometric tension were measured with Grass force-displacement transducers. The (-)epicatechin-induced relaxation was largely dependent on the presence of intact endothelium and was reversed by NG-nitro-L-arginine methyl ester 10 micromol/L or methylene blue 10 micromol/L, the inhibitors of nitric oxide-mediated relaxation. L-Arginine at 1 mmol/L antagonized the effect of L-NAME or methylene blue. Pretreatment of endothelium-intact rings with (-)epicatechin 10 micromol/L enhanced the relaxation induced by endothelium-dependent vasodilator, acetylcholine, while this concentration did not influence the endothelium-independent relaxation induced by sodium nitroprusside in the endothelium-denuded artery rings.
assistant
The results indicate that the endothelium-dependent vasodilation by (-)epicatechin is mainly mediated through nitric oxide and low concentration of (-)epicatechin augments endothelium-dependent vasorelaxation in the rat mesenteric arteries. Final Decision: yes