Kirchheim H R, Ehmke H, Hackenthal E, Löwe W, Persson P
Physiologisches Institut, Universität Heidelberg, Federal Republic of Germany.
Pflugers Arch. 1987 Nov;410(4-5):441-9. doi: 10.1007/BF00586523.
The relationship between renal artery pressure (RAP), renal blood flow (RBF), glomerular filtration rate (GFR) and the renal venous-arterial plasma renin activity difference (PRAD) was studied in 22 chronically instrumented, conscious foxhounds with a daily sodium intake of 6.6 mmol/kg. RAP was reduced in steps and maintained constant for 5 min using an inflatable renal artery cuff and a pressure control system. Between 160 and 81 mm Hg we observed a concomitant autoregulation of GFR and RBF with a high precision. The "break off points" for GRF- and RBF-autoregulation were sharp and were significantly different from each other (GFR: 80.5 +/- 3.5 mm Hg; RBF: 65.6 +/- 1.3 mm Hg; P less than 0.01). In the subautoregulatory range GFR and RBF decreased in a linerar fashion and ceased at 40 and 19 mm Hg, respectively. Between 160 mm Hg and 95 mm Hg (threshold pressure for renin release) PRAD remained unchanged; below threshold pressure PRAD increased steeply (average slope: 0.34 ng AI.ml-1.h-1.mm Hg-1) indicating that resting renin release may be doubled by a fall of RAP by only 3 mm Hg. At the "break-off point" of RBF-autoregulation (66 mm Hg) renin release was 10-fold higher than the resting level. It is concluded that under physiological conditions (normal sodium diet) GFR and RBF are perfectly autoregulated over a wide pressure range. Renin release remains suppressed until RAP falls below a well defined threshold pressure slightly below the animal's resting systemic pressure. RBF is maintained at significantly lower pressures than GFR, indicating that autoregulation of RBF also involves postglomerular vessels.(ABSTRACT TRUNCATED AT 250 WORDS)
在22只长期植入仪器、清醒的猎狐犬中进行了研究，这些犬每日钠摄入量为6.6 mmol/kg，研究了肾动脉压（RAP）、肾血流量（RBF）、肾小球滤过率（GFR）与肾静脉 - 动脉血浆肾素活性差（PRAD）之间的关系。使用可充气的肾动脉袖带和压力控制系统逐步降低RAP，并维持5分钟恒定。在160至81毫米汞柱之间，我们观察到GFR和RBF伴随着高精度的自身调节。GFR和RBF自身调节的“断点”很明显，且彼此有显著差异（GFR：80.5±3.5毫米汞柱；RBF：65.6±1.3毫米汞柱；P＜0.01）。在自身调节不足的范围内，GFR和RBF呈线性下降，分别在40和19毫米汞柱时停止。在160毫米汞柱至95毫米汞柱（肾素释放的阈值压力）之间，PRAD保持不变；低于阈值压力时，PRAD急剧增加（平均斜率：0.34 ng AI·ml⁻¹·h⁻¹·mmHg⁻¹），表明仅RAP下降3毫米汞柱就可能使静息肾素释放增加一倍。在RBF自身调节的“断点”（66毫米汞柱）处，肾素释放比静息水平高10倍。结论是，在生理条件下（正常钠饮食），GFR和RBF在很宽的压力范围内能完美地进行自身调节。肾素释放一直受到抑制，直到RAP降至略低于动物静息全身压力的明确阈值压力以下。RBF在比GFR低得多的压力下维持，表明RBF的自身调节也涉及肾小球后血管。（摘要截选至250字）
