Schwartz J H, Flamenbaum W
Am J Physiol. 1976 Jun;230(6):1582-9. doi: 10.1152/ajplegacy.1976.230.6.1582.
Previous studies of heavy metal salt-induced acute renal failure demonstrated abnormalities of fluid and solute transport by nephron segments and alterations in glomerular filtration rate and renal hemodynamics. To determine the direct effects of uranyl nitrate (UN) or HgCl2 on ion transport, their effects were studied on the isolated urinary bladder of the turtle. Unidirectional 24Na+ and 36Cl- fluxes were measured across short-circuited bladders. The addition of 0.1 mM UN to the mucosal solution resulted in a 69.9 +/- 4% (SEM) decrease in short-circuit current (SCC) without change in transepithelial resistance. Net Na+ flux (7.95 +/- 0.81 mueq/h per 8 cm2) decreased by the same magnitude as the SCC, primarily due to a 5.75 +/- 0.76 mueq/h per 8 cm2 decrease in the mucosal- (M) to-serosal (S) Na+ flux. Net Cl- flux decreased also primarily due to a decrease in M-to-S Cl- flux. Addition of 0.4 mM UN to S did not measurably affect the SCC or ion fluxes. The addition of 10 muM HgCl2 in another group of bladders reduced SCC and M-to-S Na+ flux by 81 +/- 7% without change in Cl- fluxes or resistance. The removal of either UN or HgCl2 from M by washing did not reverse the decreased SCC, but after washing addition of either dithiothreitol, 2 mM, or amphotericin B, 20 mug/ml, to M completely reversed the effects of UN or HgCl2 on SCC. These studies suggest that heavy metal salts inhibit Na+ transport by the turtle bladder without altering passive ion fluxes.
先前关于重金属盐诱导急性肾衰竭的研究表明，肾单位各节段的液体和溶质转运存在异常，肾小球滤过率和肾血流动力学也发生改变。为了确定硝酸铀酰（UN）或氯化汞（HgCl₂）对离子转运的直接影响，研究了它们对乌龟离体膀胱的作用。在短路膀胱上测量单向²⁴Na⁺和³⁶Cl⁻通量。向黏膜溶液中添加0.1 mM UN导致短路电流（SCC）下降69.9±4%（标准误），而跨上皮电阻无变化。净Na⁺通量（每8 cm²为7.95±0.81 μeq/h）下降幅度与SCC相同，主要是由于黏膜（M）到浆膜（S）的Na⁺通量每8 cm²下降5.75±0.76 μeq/h。净Cl⁻通量也下降，主要是由于M到S的Cl⁻通量减少。向S中添加0.4 mM UN对SCC或离子通量无明显影响。在另一组膀胱中添加10 μM HgCl₂使SCC和M到S的Na⁺通量降低81±7%，而Cl⁻通量和电阻无变化。通过冲洗从M中去除UN或HgCl₂并不能逆转SCC的降低，但冲洗后向M中添加2 mM二硫苏糖醇或20 μg/ml两性霉素B可完全逆转UN或HgCl₂对SCC的影响。这些研究表明，重金属盐抑制乌龟膀胱的Na⁺转运，而不改变被动离子通量。
