Ott C E, Marchand G R, Diaz-Buxo J A, Knox F G
Am J Physiol. 1976 Jul;231(1):235-9. doi: 10.1152/ajplegacy.1976.231.1.235.
Micropuncture techniques were used to evaluate the determinants of glomerular filtration in hydropenic dogs. Stop-flow and servo-null techniques were used to estimate the glomerular capillary and proximal tubule hydrostatic pressures. The validity of stop-flow estimates was verified by comparisons with direct puncture of glomerular capillaries in Munich-Wistar rats. Efferent arteriolar oncotic pressure was calculated from the filtration fraction and systemic protein concentrations. This calculation was verified in separate experiments by measurement of the protein concentration in blood collected directly from efferent arterioles. In 14 dogs, estimated glomerular capillary pressure (GCP) averaged 65.8 +/- 2.9 mmHg and proximal tubule pressure (PT) averaged 20.5 +/- 1.3 mmHg. The net hydrostatic filtration pressure (GCP - PT) of 45.3 +/- 2.7 mmHg was significantly higher than the efferent arteriolar oncotic pressure (piEA) of 33.2 +/- 2.8 mmHg (P less than .001). These findings indicate that filtration dynamics in the dog are characterized by filtration pressure disequilibrium.
采用微穿刺技术评估禁水犬肾小球滤过的决定因素。使用停流和伺服零技术来估计肾小球毛细血管和近端小管的静水压。通过与慕尼黑-维斯塔大鼠肾小球毛细血管直接穿刺的结果进行比较，验证了停流估计的有效性。根据滤过分数和全身蛋白浓度计算出出球小动脉胶体渗透压。在单独的实验中，通过测量直接从出球小动脉采集的血液中的蛋白浓度，对该计算结果进行了验证。在14只犬中，估计的肾小球毛细血管压力（GCP）平均为65.8±2.9 mmHg，近端小管压力（PT）平均为20.5±1.3 mmHg。45.3±2.7 mmHg的净静水压滤过压（GCP - PT）显著高于33.2±2.8 mmHg的出球小动脉胶体渗透压（πEA）（P <.001）。这些发现表明，犬的滤过动力学特征为滤过压力失衡。
