血管紧张素-(1-7)对二肾一夹高血压大鼠血压及血管活性物质的影响

目的观察急性血管紧张素-(1-7)[Ang-(1-7)]干预后二肾一夹(2KlC)高血压大鼠血压的变化过程,以及Ang-(1-7)对血压相关血管活性物质的影响。方法建立2KlC高血压大鼠模型后2周,经颈内静脉予Ang-(1-7)短期干预,同时多导电生理仪记录有创颈动脉压演变。放免法测定血浆AngⅡ,酶法测定血清一氧化氮(NO)、氧自由基(O2-)浓度及血清总一氧化氮合酶(NOS)、超氧化物歧化酶(SOD)活力,酶免疫法测定血浆前列腺素E2(PGE2)。结果Ang-(1-7)可造成2KlC大鼠血压降低。与降低血压状态相伴随,血清NO及血浆PGE2浓度显著升高(P<0.01),血清O2-浓度显著降低(P<0.01),血浆AngⅡ水平及血清NOS、SOD活力未受Ang-(1-7)影响。结论在高肾素-血管紧张素系统(RAS)活性状态下,Ang-(1-7)降压机制与循环NO、PGE2浓度升高及O2-浓度降低有关。

Effects of angiotensin- ( 1-7 ) on blood pressure and vasoactive factors in 2K1C hypertensive rats

Objective To observe the course of blood pressure change after acute angiotensin-(1-7)[Ang-(1-7)] infusion in two-kidney,one clip(2K1C) hypertensive rats and to explore its mechanisms.Methods Hypertension in rats were produced with a clip on the left renal artery.2 weeks after the operation,Ang-(1-7) was infused through a jugular vein catheter.Phasic arterial pressure was recorded through a carotid artery catheter by physiological recorder.Plasma angiotensin Ⅱ(AngⅡ)was determined by radioimmunoassay, serum nitric oxide(NO) and superoxide(O_2~-)concentration,nitric oxide synthase(NOS)and superoxide dismutase(SOD)activity were determined by enzyme method,plasma prostaglandin E_2(PGE_2) was measured by enzymeimmunoassay.Results Biphasic effects of Ang-(1-7) on blood pressure were marked in 2K1C rats.Simultaneously with the decline of blood pressure,serum NO and plasma PGE_2 levels elevated markedly(P<0.01),whereas the serum O_2~-concentration reduced(P<0.01).Ang-(1-7) infusion did not change plasma AngⅡ concentration.Serum NOS and SOD activity were not affected by Ang-(1-7).Conclusion In 2K1C hypertensive rats,the antihypertensive mechanisms of Ang-(1-7) related with releasing of NO,PGE_2 and lowering O_2~-levels in circulation.