口服L-精氨酸对腹主动脉缩窄后大鼠血压、心肌肥厚和血管舒张功能的影响

本文利用缩窄大鼠腹主动脉的方法制备高血压模型，观察了正常大鼠、未服和口服Ｌ－精氨酸两周的腹主动脉狭窄的大鼠的血压、心肌肥厚及血管舒张功能的改变，旨在了解Ｌ－精氨酸对腹主动脉缩窄性高血压大鼠的作用。研究发现腹主动脉狭窄后大鼠发生了严重的高血压及心肌肥厚。未服Ｌ－精氨酸的大鼠心肌肥厚，且血管环对１０－８～１０－５ｍｏｌ／Ｌ乙酰胆碱诱导的舒张反应明显减低；而Ｌ－精氨酸口服治疗两周能减轻其心肌肥厚，并部分改善乙酰胆碱诱导的血管舒张功能，但两组大鼠腹主动脉缩窄后的血压均升高，两者相比较差别无统计学意义（Ｐ＞０．０５）。结果提示：Ｌ－精氨酸（１０－５～１０－３ｍｏｌ／Ｌ）有直接舒张该大鼠血管环的作用，且呈剂量依赖关系，长期口服Ｌ－精氨酸可减轻腹主动脉缩窄性大鼠的心肌肥厚，改善其血管的舒张功能，而其血压的变化与上述作用无关。

Effect of Long-term Oral L-arginine on Vasodilation and Myocardial Hypertrophy from Rats with Aortic Coarctationinduced Hypertension

We contrasted,in normotensive and oral,not oral L-arginine hypertensive rats, the changes of blood pressure, vasodilation and myocardium.The rats after aorta coarctation had severe hypertension and myocardial hypertrophy. L-arginine administration two weeks did not prevent the development from hypertension but could decrease myocardial hypertrophy in rats with aorta coarctation (heart weight/body weight ratio 3.78±0.19 vs 4.11±0.22mg/g, P< 0.05 ).The vasodilation to acetylcholine attenuated in isolated thoracic aorta from hypertensive rats with not oral L-arginine. L-arginine (10-5~10-3mol/L) induced concentration-dependent relaxation of thoracic aorta rings taken from hypertensive rats after aorta coarctation, but no effects on isometic tension of thoracic aorta rings from normotensive or oral L-arginine hypertensive rats.These findings suggest that L-arginine may attenu ate myocardial hypertrophy and improve vasodilation on hypertensive rats.This effects did not depend on the change of blood pressure.