Martínez Ayala S O, Vázquez Cruz B, Sánchez Mendoza A, Cortés García J C, Escalante Acosta B A
Departamento de Farmacología y Toxicología, Centro de Investigación y de Estudios Avanzados, IPN.
Arch Inst Cardiol Mex. 1998 Jul-Aug;68(4):289-94.
Nitric oxide is an important regulator of vascular tone. Deficiencies in nitric oxide release have been implicated in hypertension. In the present study we evaluated vascular reactivity to phenylephrine and acetylcholine in isolated aorta ring preparations from sham and aortic coarctation-induced hypertensive rats and nitric oxide release under resting conditions and after stimulation with acetylcholine. Aortic vessels were divided in upper segment and lower segment in relation to the coarctation; both segments were tested for vascular reactivity and nitric oxide release. Phenylephrine produced higher vasoconstriction in upper segments from hypertensive rats compared to sham operated animals. Lower segments in both experimental groups were not significantly different. Relaxation produced by acetylcholine showed a higher EC50 in the upper segments from hypertensive rats; lower segments in both experimental groups were not significantly different. Aortic rings from hypertensive rats had a higher level of nitric oxide release compared to sham operated rats. Lower segments from hypertensive rats released significantly more nitric oxide. These results suggest that shear stress induced nitric oxide release in lower aortic segments from aortic coarctation-induced hypertensive rats.
一氧化氮是血管张力的重要调节因子。一氧化氮释放不足与高血压有关。在本研究中，我们评估了假手术组和主动脉缩窄诱导的高血压大鼠离体主动脉环制剂对去氧肾上腺素和乙酰胆碱的血管反应性，以及静息条件下和乙酰胆碱刺激后一氧化氮的释放。根据缩窄情况，将主动脉血管分为上段和下段；对两段血管均进行血管反应性和一氧化氮释放测试。与假手术动物相比，去氧肾上腺素在高血压大鼠上段产生更高的血管收缩作用。两个实验组的下段无显著差异。乙酰胆碱产生的舒张作用在高血压大鼠上段显示出更高的半数有效浓度（EC50）；两个实验组的下段无显著差异。与假手术大鼠相比，高血压大鼠的主动脉环一氧化氮释放水平更高。高血压大鼠的下段释放的一氧化氮明显更多。这些结果表明，剪切应力诱导主动脉缩窄诱导的高血压大鼠主动脉下段释放一氧化氮。
