锂对肾小管酸化动力学的损害。

Impairment of the renal tubular acidification kinetics by lithium.

作者信息

MacLaughlin M, Mello-Aires M

机构信息

Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brasil.

出版信息

Braz J Med Biol Res. 1989;22(12):1531-3.

PMID:2641361

Abstract

We studied the kinetics of HCO3- reabsorption in the middle proximal (MPT) and distal convoluted tubules (DCT) by measuring continuously intratubular pH with Sb-microelectrodes in stopped-flow microperfusion (HCO3-, 30 mM Ringer) experiments. Male Wistar rats (240-280 g) were injected ip with LiCl (4 mEq kg-1 day-1) for 4 days (Li) and were compared to controls (C). Steady-state pH increased in MPT from 6.64 +/- 0.02 (57) to 6.89 +/- 0.02 (45), mean +/- SEM (number of measurements) on tissue from 13 rats in each group, and from 6.87 +/- 0.05 (30) to 7.08 +/- 0.01 (63) in DCT. HCO3- reabsorption decreased from 1.32 +/- 0.08 (57) to 0.96 +/- 0.04 (45) nmol cm-2 s-1 in MPT and from 0.85 +/- 0.07 (30) to 0.45 +/- 0.04 (63) in DCT. These data indicate that lithium affected the acidification mechanism in MPT and DCT, probably through an impairment of the Na(+)-H+ antiport in both tubular segments.

摘要

我们通过在停流微灌注（30 mM 林格氏液中的 HCO₃⁻）实验中使用锑微电极连续测量肾小管内 pH 值，研究了近端中段（MPT）和远端曲管（DCT）中 HCO₃⁻重吸收的动力学。雄性 Wistar 大鼠（240 - 280 g）腹腔注射 LiCl（4 mEq kg⁻¹ 天⁻¹），持续 4 天（Li 组），并与对照组（C 组）进行比较。每组 13 只大鼠组织的 MPT 中稳态 pH 值从 6.64 ± 0.02（57）升高到 6.89 ± 0.02（45），DCT 中从 6.87 ± 0.05（30）升高到 7.08 ± 0.01（63），均值 ± 标准误（测量次数）。MPT 中 HCO₃⁻重吸收从 1.32 ± 0.08（57）降至 0.96 ± 0.04（45）nmol cm⁻² s⁻¹，DCT 中从 0.85 ± 0.07（30）降至 0.45 ± 0.04（63）。这些数据表明锂可能通过损害两个肾小管节段中的 Na⁺-H⁺反向转运体影响了 MPT 和 DCT 中的酸化机制。