桑白皮丙酮提取物舒张血管作用机制研究

Study on Vasodilating Mechanism of the Acetone Extract from Cortex Mori

目的研究桑白皮丙酮提取物的舒张血管作用及作用机制。方法用去甲肾上腺素致豚鼠肠系膜微血管收缩,研究其整体的舒张血管作用;在添加或不添加优降糖或普萘洛尔,或去血管内皮情况下,观察其对离体大鼠胸主动脉环的作用;硝酸还原酶法测定给予药物后大鼠血浆和血管的NO以及血管NOS、cNOS、iNOS含量的变化。结果桑白皮丙酮提取物有抑制去甲肾上腺素收缩豚鼠肠系膜微血管的作用,抑制苯肾上腺素(10μmol/L)收缩离体大鼠胸主动脉环的作用,预加优降糖(1μmol/L)或普萘洛尔((3μmol/L)后仍然有松弛作用;大鼠胸主动脉环去内皮后药物无松弛作用,反而起收缩作用;显著升高血管的NO和NOS、cNOS的含量,对大鼠血浆的NO和血管iNOS的含量影响不大。结论桑白皮丙酮提取物的舒张血管作用机制可能与血管释放NO和促进cNOS、NOS合成有关。

Objective To study the vasodilating effect of the acetone- extract (AE) from Cortex Mori (CM) and its vasodilating mechanism. Methods Guinea pig models with contraction of mesentery blood capillary induced by noradrenalin were used to study the in- vivo vasodilating effects of AE from CM. In- vitro effect of AE from CM on rat thoracic aortic ring was observed. The contents of nitric oxide (NO), nitric oxide synthase (NOS), constitutive NOS(cNOS) and inducible (iNOS) in plasma and aortic tissue were determined by method of nitroreductase chromatometry. Results AE from CM had vasodilating effect on the contracti on of mesentery blood capillary in guinea pigs and the contraction of rat thoracic aortic ring induced by 10μ mol/L phenylephrine, even under the condition of pre- treating with glibenclamide (1 μ mol/L) or propranolol (3 μ mol/L). When the endothelium of the rat thoracic aortic ring was removed, AE from CM had not vasodilating effect but constrictive effect. AE from CM could also increase the contents of NO, NOS and cNOS in the aortic tissue and had no obvious effect on the NO content in plasma and iNOS in aortic tissue of rats. Conclusion The vasodilating mechanism of AE from CM may be related to promoting the release of NO from endothelium of blood vessel and synthesis of NOS and cNOS in aortic tissue.