Salom M G, Fenoy F J, Inglés A C, Martínez L, Quesada T
Departamento de Fisiología, Facultad de Medicina, Murcia, Spain.
Am J Physiol. 1989 Aug;257(2 Pt 2):R365-9. doi: 10.1152/ajpregu.1989.257.2.R365.
In the present study, we have evaluated whether the hemodynamic effects of atrial natriuretic peptide (ANP) infusion in two-kidney, one-clip (2K, 1C) hypertensive rats are mediated by inhibition of the renin-angiotensin system (RAS). Hemodynamic determinations were performed by thermodilution in conscious, chronically instrumented animals. ANP (1.5 micrograms.kg-1.min-1) and converting-enzyme (CE) inhibitor captopril (1 mg/kg plus 1 mg.kg-1.h-1), produced a similar fall of blood pressure through different hemodynamic mechanisms. ANP induced hypotension by decreasing cardiac index (CI; from 337.3 +/- 24.9 to 255.1 +/- 21.3 ml.min-1.kg-1, P less than 0.001), whereas a fall in total peripheral resistance (TPR) was observed during CE inhibition (from 0.568 +/- 0.02 to 0.488 +/- 0.02 mmHg.min.ml-1.kg, P less than 0.05). In addition, the ANP-induced decrease in CI was not significantly modified by previous CE inhibition. Furthermore, the decrease in TPR induced by CE inhibition did not change when CE inhibitor was administered during ANP treatment. The results of the present study indicate that the acute hemodynamic responses to ANP in 2K, 1C hypertensive rats are not mediated through antagonism of the vasoconstrictor actions of the RAS.
在本研究中，我们评估了心房利钠肽（ANP）输注对两肾一夹（2K，1C）高血压大鼠的血流动力学效应是否由肾素-血管紧张素系统（RAS）的抑制介导。血流动力学测定通过热稀释法在清醒、长期植入仪器的动物中进行。ANP（1.5微克·千克⁻¹·分钟⁻¹）和转化酶（CE）抑制剂卡托普利（1毫克/千克加1毫克·千克⁻¹·小时⁻¹）通过不同的血流动力学机制使血压产生相似程度的下降。ANP通过降低心脏指数（CI；从337.3±24.9降至255.1±21.3毫升·分钟⁻¹·千克⁻¹，P＜0.001）诱导低血压，而在CE抑制期间观察到总外周阻力（TPR）下降（从0.568±0.02降至0.488±0.02毫米汞柱·分钟·毫升⁻¹·千克，P＜0.05）。此外，先前的CE抑制并未显著改变ANP诱导的CI下降。而且，当在ANP治疗期间给予CE抑制剂时，CE抑制诱导的TPR下降并未改变。本研究结果表明，2K，1C高血压大鼠对ANP的急性血流动力学反应并非通过拮抗RAS的血管收缩作用介导。
