L—精氨酸对内皮完整和去内皮大鼠主动脉的松弛作用

目的 :探讨 L-精氨酸对离体大鼠主动脉的松弛作用。方法 :将内皮完整和去内皮的大鼠主动脉环悬挂于器官浴槽中 ,测定离体血管的收缩张力变化。所有的实验在浴液中都加入吲哚美辛 ( 1× 10 - 5mol/L)和普萘洛尔 ( 3× 10 - 6mol/L)。标本在生理盐溶液中经不同时间孵育后 ,以去甲肾上腺素使其收缩 ,加入不同浓度的 L-精氨酸 ,观察血管松弛反应。结果 :标本孵育时间 >2 h时 ,L-精氨酸使内皮完整和去内皮的动脉环产生浓度和时间依赖性松弛效应 ,而甲烯蓝及左旋硝基精氨酸使其松弛效应减弱。结论 :内皮细胞和血管平滑肌细胞均具有与血管舒张有关的 L-精氨酸 -EDRF( NO)系统 ,它对血管张力的调节起重要作用

L-ARGININE EVOKES RELAXATIONS OF THE RAT AROTA IN BOTH THE PRESENCE AND ABSECE OF ENDOTHELIAL CELLS

Objective:The effect of L-arginine on the reactivity of isolated vascular preparations was studied.Methods: Rings of rat arota, with or without endothelium, were suspended in organ chambers for the measurement of isometric force. All experiments were performed in the presence of indomethacin (10 -5 mol/L ) to prevent the production of vasoactive prostanoids and binding of norepinephrine with beta receptor. After various incubation periods in physiological salt solution, they were contracted with norepinephrine (10 -6 mol/L) before the addition of cumulative concentrations of L-arginine. The relations evoked by L-arginine were observed. Results: Results showed that when the incubation period was longer than 2h, the L-arginine were evoked concentration and time-dependent relaxation in preparations both with and without endothelium. The relaxation evoked by L-arginine was impaired by N G-nitro-L-arginine and methylene blue. Conclusions: Our results indicated that both the endothelial cells and the vascular smooth muscle possess biochemical pathways converting L-arginine to nitric oxide and it's an important regulatory factor for the force of vascular smooth muscle.