Persson P B, Ehmke H, Nafz B, Kirchheim H R
I. Physiologisches Institut der Universität Heidelberg, Federal Republic of Germany.
Am J Physiol. 1990 Feb;258(2 Pt 2):F364-70. doi: 10.1152/ajprenal.1990.258.2.F364.
The effects of a moderate reflex activation of the sympathetic nervous system on renal blood flow (RBF) and glomerular filtration rate (GFR) were studied in 29 experiments on seven conscious foxhounds. Autoregulation parameters were derived by a stepwise reduction of renal artery pressure of 10-mmHg decrements. An occlusion of both common carotid arteries (CCO) was used as a moderate sympathetic stimulus. This procedure did not influence the basal levels of RBF and GFR. However, the lower limits of autoregulation were considerably shifted (RBF, control 63 +/- 3 mmHg vs. CCO 91 +/- 8 mmHg, P less than 0.01; GFR, control 77 +/- 5 mmHg vs. CCO 102 +/- 5 mmHg, P less than 0.01). CCO also affected the rate by which RBF and GFR decreased below the autoregulatory range (subautoregulatory function: RBF, control y = 0.056x - 1.4 vs. CCO y = 0.037x - 0.9 ml.mmHg-1.g-1, P less than 0.05; GFR, control y = 0.0089x - 0.4 vs. CCO y = 0.0054x - 0.28 ml.mmHg-1.g-1, P less than 0.05). An alpha-blockade via intrarenal prazosin infusions markedly inhibited these effects of CCO. These findings demonstrate the failure of autoregulation below 102 mmHg for GFR and 91 mmHg for RBF during sympathetic activation, and they may be of clinical importance for situations that are characterized by a high sympathetic tone.
在对7只清醒猎狐犬进行的29次实验中，研究了交感神经系统适度反射激活对肾血流量（RBF）和肾小球滤过率（GFR）的影响。通过以10mmHg的递减幅度逐步降低肾动脉压力来得出自动调节参数。双侧颈总动脉闭塞（CCO）用作适度的交感神经刺激。该操作不影响RBF和GFR的基础水平。然而，自动调节的下限有相当大的偏移（RBF，对照组63±3mmHg，CCO组91±8mmHg，P＜0.01；GFR，对照组77±5mmHg，CCO组102±5mmHg，P＜0.01）。CCO还影响RBF和GFR降低至自动调节范围以下的速率（自动调节功能以下：RBF，对照组y = 0.056x - 1.4，CCO组y = 0.037x - 0.9ml·mmHg⁻¹·g⁻¹，P＜0.05；GFR，对照组y = 0.0089x - 0.4，CCO组y = 0.0054x - 0.28ml·mmHg⁻¹·g⁻¹，P＜0.05）。通过肾内注入哌唑嗪进行α阻断可显著抑制CCO的这些作用。这些发现表明，在交感神经激活期间，GFR低于102mmHg且RBF低于91mmHg时自动调节功能失效，它们可能对以高交感神经张力为特征的情况具有临床重要性。
