根皮素的心血管保护作用研究

目的 研究根皮素对狗冠状动脉舒张特征的影响及其机制.方法 制备狗冠状动脉血管环,固定于盛有K-H液的恒温肌槽内,并观察等长时血管张力的变化.结果 10 μmol·L-1或30 μmol· L-1 L根皮素使KCl及无钙K-H液中CaCl2量效曲线明显右移,使血管环敏感性和最大收缩反应明显降低.30 μmol· L-1根皮素在50 mmol· L-1 KCl预收缩的离体冠脉血管环产生一个明显的急性舒张,加入Nω-L-硝基精氨酸1×10-4mol·L-1、普蔡洛尔1×10-5 mol· L-1、亚甲蓝1×10-5 mol·L-1、二硝酸异山梨醇酯(吲哚美辛)1×10-5 mol·L-1及去内皮细胞后,根皮素的急性舒张血管作用不受影响.结论 根皮素在离体冠脉血管环的舒张效应主要是通过抑制电压依赖性钙通道实现的.根皮素的这种舒张效应与NO、内皮、β肾上腺素受体和前列腺素类皆无关.

Study on cardiovascular protective effects of phloretin

Objective To investigate the influence of phloretin on relaxative characteristics of coronary arteries in dog and its mechanism.Methods The arterial ring of canine coronary artery was prepared and suspended in organ baths containing Krebs-Henseleit solution,and then isometric tension was measured.Results Phloretin 10 μmol·L-1 or 30 μmol·L-1 caused the does-response contractile curve of KCl in K-H solution and CaCl2 in Ca2+-free K-H solution shifted to the rightward,and their sensitivies and the values of maximum contractions were decreased.Phloretin 30 μmol/L could produce a significantly acute relaxation on 50 mmol/L KCl-precontractile isolated coronary rings.After incubation with inhibitor of nitric oxide synthase Nω-L-nitro-arginine 1×10-4 mol·L-1,propranolo1× 10-5 mol·L-1,methylene blue 1×10-5 mol·L-1,indomethacin 1×10-5 mol·L-1 or endothelium removal,relaxations induced by phloretin had no change.Conclusion Phloretin mediated relaxations of isolated coronary strips mianly realize via inhibition of voltage-dependent calcium channels(VDCCs).The relaxant effect of phloretin is not related to NO,endothelium and β-adrenoceptors as well as prostaglandins.