Homeostatic efficiency of tubuloglomerular feedback in hydropenia, euvolemia, and acute volume expansion.
Homeostatic efficiency of tubuloglomerular feedback in hydropenia, euvolemia, and acute volume expansion.
复制标题
缺水、血容量正常和急性容量扩张时肾小球小管反馈的稳态效率。
DOI：
10.1152/ajprenal.1993.264.6.f930
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Blantz,RC
中科院分区：
文献类型：
--
作者：
Thomson,SC;Blantz,RC
在闭环微穿刺研究中，我们采用微扰分析的方法评估了失动素麻醉的慕尼黑- wistar大鼠小管肾小球反馈（TGF）系统的稳态效率。在体内研究肾单位在缺水（HYD, n = 17）、EUV （EUV, n = 23）和急性等渗细胞外体积扩张（EXP, n = 15）条件下的作用。用微灌注仪干扰自由流动肾元近端小管流动。用无创光学技术测量了微扰（VH）上游的流量（VM）。利用多项式回归估计了VH对VM的依赖关系。通过使用分数补偿（C = -dVM/dVH）作为稳态效率的指标，我们构建了效率曲线（C vs. VH）。在VH = 0时，随着体积状态的减小，C趋于较高，但影响不显著。C的最大值各组间无差异。效率曲线随着体积的增加而向左移动（P < 0.03, HYD vs. EXP），这表明TGF系统通过改变效率曲线来适应急剧的体积增加，从而有利于血管扩张的作用。
We assessed the homeostatic efficiency of the tubuloglomerular feedback (TGF) system in Inactin-anesthetized Munich-Wistar rats by use of perturbation analysis in closed-loop micropuncture studies. Nephrons were studied in vivo under conditions of hydropenia (HYD, n = 17), euvolemia (EUV, n = 23), and acute isoncotic extracellular volume expansion (EXP, n = 15). Proximal tubular flow was perturbed in free-flowing nephrons with a microperfusion apparatus. Flow rate (VM) was measured upstream from the perturbation (VH) by a noninvasive optical technique. The dependence of VM on VH was estimated by polynomial regression. By using fractional compensation (C = -dVM/dVH), as an index of homeostatic efficiency, we constructed efficiency profiles (C vs. VH). At VH = 0, C tended toward higher values with decreasing volume status, although the effect did not achieve significance. The maximum value of C did not differ between groups. The efficiency profiles shifted leftward with each increment in volume (P < 0.03, HYD vs. EXP), suggesting that the TGF system adapts to acute increments in volume by shifting the efficiency profile in favor of a vasodilatory role.