1. The feedback control of arterial blood pressure by the kidney in the range of hours was investigated in resting, conscious foxhounds. 2. A servo-control device (connected to an aortic occlusive cuff implanted above both renal arteries) was used to maintain a constant pressure difference of 20 mmHg between aortic pressure measured proximal (mean arterial blood pressure: MAP) and distal (renal artery pressure: RAP) to the aortic cuff. 3. Protocol 1 (n = 6) served as a 4 h time control without intervention, protocol 2 (n = 6) consisted of three periods: after a control of 20 min duration, the servo-control device was activated for 180 min; this was followed by a recovery period of 40 min. Protocol 3 (n = 6) was as protocol 2, but during converting-enzyme inhibition. 4. Servo-control increased plasma renin activity (PRA) transiently from 0.5 ng angiotensin I (AI) ml-1 h-1 to a peak value of 2.4 ng AI ml-1 h-1, subsequently both RAP and MAP rose to reach a new steady state. During this increase in RAP, PRA declined to 1.4 ng AI ml-1 h-1. 5. On average, the compensation of the pressure decrease sensed by the kidney amounted to 63% of the error signal (closed-loop gain of 0.63 +/- 0.1). 6. Converting-enzyme inhibition reduced this closed-loop gain significantly (protocol 2 vs. protocol 3, 0.63 +/- 0.1 vs. 0.15 +/- 0.1; P < 0.05). 7. It is concluded, that the kidney plays an important role in medium-term blood pressure regulation, most probably via the renin-angiotensin system.
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机译：1.在静息的，有意识的猎狐犬中研究了肾脏在数小时范围内对动脉血压的反馈控制。 2.使用伺服控制设备（连接至植入在两个肾动脉上方的主动脉闭塞套）将近端（平均动脉压：MAP）和远端（肾动脉压）之间测得的主压保持恒定的压力差20 mmHg。 ：RAP）插入主动脉套囊。 3.协议1（n = 6）可以在4小时内不受干扰地进行控制，协议2（n = 6）由三个周期组成：控制20分钟后，激活伺服控制设备180分钟；之后是40分钟的恢复时间。方案3（n = 6）与方案2相同，但在转化酶抑制过程中。 4.伺服控制使血浆肾素活性（PRA）从0.5 ng血管紧张素I（AI）ml-1 h-1瞬时增加到2.4 ng AI ml-1 h-1的峰值，随后RAP和MAP均上升新的稳定状态。在RAP增加期间，PRA降至1.4 ng AI ml-1 h-1。 5.平均而言，肾脏感知到的压力下降的补偿量为误差信号的63％（闭环增益为0.63 +/- 0.1）。 6.转化酶抑制显着降低了该闭环增益（方案2与方案3，0.63 +/- 0.1与0.15 +/- 0.1； P <0.05）。 7.结论是，肾脏在中期血压调节中起着重要作用，很可能是通过肾素-血管紧张素系统。
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