论文部分内容阅读
我们先前已在麻醉大鼠中用锂清除率方法从全肾水平证实,脑室内注射高张盐水(icv.HS)引起的利尿和利尿钠反应是由于肾小球滤过率增加和近球小管重吸收能力降低。本实验用肾小管微穿刺方法从肾单位水平进一步观察icv.HS对浅表肾单位的单个肾单位肾小球滤过率以及近曲小管和髓袢的重吸收的影响。实验在麻醉大鼠中进行。icv.HS后,单个肾单位肾小球滤过率从39.6±1.9nl/min增加至48.8±2.0nl/min(P<0.001);近曲小管末段小管液流量从20.5±1.4nl/min增加至28.4±2.0nl/min(P<0.001);小管液菊糖浓度与血浆菊糖浓度的比值从1.98±0.98降低至1.69±0.05(P<0.01)。根据上述数据计算得到的近曲小管重吸收分数从49.2±2.2％下降至41.7±1.8％(P<0.001),而近曲小管的绝对重吸收无明显改变。这些结果与用锂清除率方法获得的结果相符合。icv.HS后,髓袢的绝对重吸收升高,而重吸收分数下降。上述结果表明刺激脑内渗透压感受器可增加浅表肾单位的肾小球滤过率,并降低近曲小管的重吸收能力,从而增加髓袢的负荷,使髓袢的绝对重吸收增加。本实验结果不能排除icv.HS对髓袢的重吸收过程具有直接影响的可能性。
We have previously demonstrated from the whole-kidney level using lithium clearance in anesthetized rats that diuretic and natriuretic reactions due to intracerebroventricular injection of hypertonic saline (icv.HS) are due to an increase in glomerular filtration rate and parietal tubular Reduce reabsorption capacity. In this experiment, the effect of icv.HS on the glomerular filtration rate of single nephron in superficial nephrons and the reabsorption of proximal tubules and medulla oblongata were further observed by using the method of tubule micro-puncture from the nephron level. Experiments were performed in anesthetized rats. The glomerular filtration rate of single nephron was increased from 39.6 ± 1.9nl / min to 48.8 ± 2.0nl / min (P <0.001) after icv.HS. The proximal tubule fluid flow was increased from 20.5 ± 1.4nl / min To 28.4 ± 2.0nl / min (P <0.001). The ratio of tubule inulin and plasma inulin concentration decreased from 1.98 ± 0.98 to 1.69 ± 0.05 (P <0.01). The proximal tubule reabsorption fraction calculated from the above data decreased from 49.2 ± 2.2% to 41.7 ± 1.8% (P <0.001), whereas the absolute reabsorption of proximal tubule did not change significantly. These results are consistent with the results obtained using the lithium clearance method. After icv.HS, the absolute reabsorption of medulla increased, while the reabsorption fraction decreased. These results indicate that stimulation of intracerebral pressure receptors increases the glomerular filtration rate of superficial renal units and decreases the reabsorption capacity of proximal convoluted tubules, thereby increasing the load of medulla and increasing the absolute reabsorption of medulla. The results of this experiment can not rule out the possibility that icv.HS has a direct effect on the reabsorption of medulla oblongata.