Maturation of rat proximal tubule chloride permeability
Maturation of rat proximal tubule chloride permeability
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DOI：
10.1152/ajpregu.00257.2005
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发表时间：
2005-12-01
影响因子：
2.8
通讯作者：
Quigley, R
中科院分区：
文献类型：
--
作者：
Baum, M;Quigley, R
我们以前已经表明，新生兔肾小管具有较低的氯化物渗透性，但与成人近端小管相比，甘露醇渗透性。与成人相比，新生儿近端的氯化物渗透性较低，这一令人惊讶的发现影响了该部分的净氯化物转运，该部分重吸收了成人中60%的过滤氯化物。然而，这种氯渗透性的成熟差异可能不适用于其他物种。本体外微灌注研究直接检查了氯化物和甘露醇渗透性在体外灌注大鼠近端小管在出生后的成熟。新生大鼠近曲小管的甘露醇渗透率为6.3 +/- 1.3 × 10（-5）cm/s，成年大鼠近曲小管的氯离子渗透率为16.1 +/- 2.3 × 10（-5）cm/ s（P < 0.01）。大鼠近端直小管的氯渗透性也有成熟性增加（5.1 +/- 0.6 x 10（-5）cm/ s vs. 9.3 +/- 0.6 x 10（-5）cm/s，P < 0.01）。碳酸氢盐-氯化物渗透率无成熟变化大鼠近端直小管（PST）和近端曲小管（PCT）或钠-氯渗透性中的P-HCO 3/PC 1（P-Na/P-C1）;然而，在本发明中，近曲小管P-Na/ P-C1随生后发育而明显下降（新生儿1.31 ± 0.12 vs成人0.75 ± 0.06，P < 0.001）。在PCT中通过电流注入和电缆分析测量的跨上皮电阻没有差异，但PST有成熟的下降（7.2 +/- 0.8 vs. 4.6 +/- 0.1 Ω（.）cm（2），P < 0.05。这些研究表明，有成熟的变化，在大鼠细胞旁途径，影响净NaCl运输在发展过程中。
We have previously shown that neonate rabbit tubules have a lower chloride permeability but comparable mannitol permeability compared with adult proximal tubules. The surprising finding of lower chloride permeability in neonate proximals compared with adults impacts net chloride transport in this segment, which reabsorbs 60% of the filtered chloride in adults. However, this maturational difference in chloride permeability may not be applicable to other species. The present in vitro microperfusion study directly examined the chloride and mannitol permeability using in vitro perfused rat proximal tubules during postnatal maturation. Whereas there was no maturational change in mannitol permeability, chloride permeability was 6.3 +/- 1.3 x 10(-5) cm/s in neonate rat proximal convoluted tubule and 16.1 +/- 2.3 x 10(-5) cm/ s in adult rat proximal convoluted tubule (P < 0.01). There was also a maturational increase in chloride permeability in the rat proximal straight tubule (5.1 +/- 0.6 x 10(-5) cm/ s vs. 9.3 +/- 0.6 x 10(-5) cm/s, P < 0.01). There was no maturational change in bicarbonate-to-chloride permeabilities (P-HCO3/PC1) in the rat proximal straight tubules (PST) and proximal convoluted tubules (PCT) or in the sodium-to-chloride permeability (P-Na/P-C1) in the proximal straight tubule; however, there was a significant maturational decrease in proximal convoluted tubule P-Na/ P-C1 with postnatal development (1.31 +/- 0.12 in neonates vs. 0.75 +/- 0.06 in adults, P < 0.001). There was no difference in the transepithelial resistance measured by current injection and cable analysis in the PCT, but there was a maturational decrease in the PST (7.2 +/- 0.8 vs. 4.6 +/- 0.1 Omega (.) cm(2), P < 0.05). These studies demonstrate there are maturational changes in the rat paracellular pathway that impact net NaCl transport during development.