抑制血管紧张素Ⅱ1型受体对自发性高血压大鼠阻力血管节律性振荡舒缩的作用

Inhibitory Effect of Angiotensin Ⅱ Recepter Type 1 Blocker on The Rhythmic Oscillatory Vasomotion in Resistance Vessel from Spontaneously Hypertensive Rats

目的观察抑制血管紧张素Ⅱ1型受体对自发性高血压大鼠(SHR)阻力血管节律性振荡舒缩的作用。方法采用小血管张力测量仪测定SHR对照组、替米沙坦[5 mg/(kg·d)]组和咪哒普利[3 mg/(kg·d)]组离体肠系膜上动脉Ⅱ级分支血管环对不同浓度乙酰胆碱、硝酸甘油的反应性及对血管紧张素Ⅱ、去甲肾上腺素诱导的节律性振荡舒缩反应。结果1)第16周时,替米沙坦组和咪哒普利组鼠尾动脉收缩压明显低于对照组(P<0.01)。2)与对照组相比,替米沙坦和咪哒普利能显著增强SHR肠系膜动脉血管环对乙酰胆碱(10^(-6)～10^(-4)mol/ L)的舒张反应(P<0.01);替米沙坦,而不是咪哒普利,增强血管环对硝酸甘油(10^(-5)mol/L)的反应性(P<0.05)。3)替米沙坦,而不是咪哒普利,显著降低血管环对血管紧张素Ⅱ(10^(-6)mol/L)和去甲肾上腺素(10^(-5)mol/L)诱导的节律性振荡舒缩反应(P<0.01)。结论替米沙坦和咪哒普利能显著降低SHR收缩压;替米沙坦可增强SHR肠系膜动脉内皮依赖和非内皮依赖的血管舒张功能,并显著降低SHR肠系膜动脉节律性振荡舒缩反应;咪哒普利虽能改善SHR肠系膜动脉内皮依赖性舒张功能,而对SHR肠系膜动脉节律性振荡舒缩反应无作用。

Objective The goal of the present study was to investigate the inhibitory effeet of angiotensin Ⅱ reeeptor type 1 bloeker on the rhythmie oseillatory vasomotion in resistanee vessel obtained from spontaneously hypertensive rat（SHR）. Methods The rats aged 18 months were divided into three groups： SHRs eontrol group （n =6）, telmisartan group Fn=6, 5 mg/（kg · d）] and imidapril group Fn=6, 3 mg/（kg · d）]. After telmisartan and imidapril treatment for sixteen weeks, rings of seeond braneh of superior mesenterie arteries were rapidly isolated and suspended in organ ehambers, whieh eontained 5 mL PBS solution （37 ℃） aerated with 95% O2 and 5% CO2 and eonneeted to foree transdueers（ Danish Myo Teehnology, Denmark） for isometrie tension reeording. Different eoneentrations of aeetyleholine（Aeh） and nitroglyeerine（NTG） were added to the ehamber respeetively and the ehange of isometrie tension was reeorded. Rhythmie oseillatory vasomotion indueed by Ang Ⅱ （ 10^-6 mol/L） or NE （ 10^-5 mol/L）were investigated. Results 1） Telmisartan and imidapril reduee blood pressure signifieantly （P〈0. 01）; 2） Telmisartan and imidapril enhaneed endothelium-dependent relaxation of the rings indueed by Aeh（10^-6-10^-4 mol/L） as eompared with eontrol （P〈0. 01）. Telmisartan, but not imidapril, aeeentuated, endothelium-independent relaxation of the rings evoked by NTG（ 10^-5 mol/L） and redueed the magnitude of rhythmie oseillatory vasomotion indueed by Ang Ⅱ （ 10^-6 mol/L） or NE（ 10^-5 mol/L） （ P〈0. 01 ）. Conclusion The results indieate that both telmisartan and imidapril reduee blood pressure of SHR signifieantly; telmisartan enhanee endothelium-dependent and endothelium-independent vaseular relaxation, with attenuating rhythmie oseillatory vasomotion in mesenterie artery. Although imidapril improve the endothelium-dependent vaseular relaxation signifieantly but has little effeet on rhythmie oseillatory vasomotion in mesenterie artery.