Tubuloglomerular feedback control of distal fluid delivery: effect of extracellular volume.
Tubuloglomerular feedback control of distal fluid delivery: effect of extracellular volume.
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远端液体输送的肾小球反馈控制：细胞外容量的影响。
DOI：
10.1152/ajprenal.1986.250.6.f1024
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Mason,J
中科院分区：
文献类型：
--
作者：
Moore,LC;Mason,J
采用闭环反馈微穿刺法，观察了水缺乏大鼠（CON）、中老年大鼠（HEM）和饮水给予脱氧皮质酮（DOC）和0.6%生理盐水的大鼠的肾小管-肾小球反馈（TGF）和远端液体输送的调节。每个肾单位用四个样品测量远端递送和TGF响应曲线：自发的早期远端收集，在肾单位液体负荷的中度（7.5 nl/min）和饱和（30 nl/min）扰动期间的两个远端收集，以及在TGF抑制期间测量单肾单位肾小球滤过率（SNGFR）的近端收集。DOC组的动脉压、远端前容量重吸收、SNGFR和早期远端血流均显著高于HEM组; CON组的数值介于两者之间。除了在HEM中更大的最大TGF反应外，所有三组的标准化TGF反应相似，远端液体输送的调节也相似。然而，TGF起始阈值和TGF工作点（由早期远端血流和SNGFR的自发率定义）被重置，使得DOC的远端液体输送和SNGFR高于HEM，肾钠排泄也是如此。结果表明，当细胞外液体积改变时，TGF稳定远端液体输送的水平被重置。
A closed-feedback loop micropuncture method was used to examine tubuloglomerular feedback (TGF) and the regulation of distal fluid delivery in hydropenic rats (CON), moderately hemorrhaged rats (HEM), and rats given desoxycorticosterone (DOC) and 0.6% saline to drink. Distal delivery and TGF response curves were measured with four samples per nephron: a spontaneous early distal collection, two distal collections during moderate (7.5 nl/min) and saturating (30 nl/min) perturbations in nephron fluid load, and a proximal collection to measure single-nephron glomerular filtration rate (SNGFR) during TGF inhibition. Arterial pressure, predistal volume reabsorption, SNGFR, and early distal flow were significantly higher in DOC than in HEM; the CON group exhibited intermediate values. Except for a greater maximum TGF response in HEM, the normalized TGF responses were similar in all three groups, as was the regulation of distal fluid delivery. However, the TGF onset threshold and the TGF operating point, defined by the spontaneous rates of early distal flow and SNGFR, were reset such that distal fluid delivery and SNGFR were higher in DOC than in HEM, as was renal sodium excretion. The results show that the level around which TGF stabilizes distal fluid delivery is reset when extracellular fluid volume is altered.