哇巴因、阿米洛利和抗利尿激素对林蛙（Rana temporaria）离体皮肤上皮钠转运池的影响。

Effect of ouabain, amiloride, and antidiuretic hormone on the sodium-transport pool in isolated epithelia from frog skin (Rana temporaria).

作者信息

Nielsen R

出版信息

J Membr Biol. 1982;65(3):221-6. doi: 10.1007/BF01869965.

Abstract

When tracer Na+ is added to the solution bathing the apical side of isolated epithelia the observed transepithelial tracer influx increases with time until a steady state is reached. The build-up of the tracer flux follows a single exponential course. The halftime for this build-up under control conditions was 0.92 +/- 0.06 min, and in the presence of ouabain 4.51 +/- 0.7 min. It is shown that the calculated Na+-transport pool is located in the cells. The Na+-transport pool under control conditions was 35.6 +/- 3.4 nmol/cm2, which corresponds to an intracellular Na+ concentration of 7.9 mM. Activation of the active Na+ transport by addition of antidiuretic hormone resulted in a highly significant increase in the Na+ transport pool, and inhibition of the transcellular Na+ transport with amiloride resulted in a decrease in the Na+-transport pool. Furthermore, the active Na+ transport increased along an S-shaped curve with increasing intracellular Na+ concentration (Na+-transport pool). The Na+ pump was found to be half saturated at an intracellular Na+ concentration of 12.5 mM.

摘要

当将示踪剂Na⁺添加到浸泡分离上皮细胞顶端侧的溶液中时，观察到的跨上皮示踪剂流入量随时间增加，直至达到稳态。示踪剂通量的积累遵循单一指数过程。在对照条件下，这种积累的半衰期为0.92±0.06分钟，在哇巴因存在的情况下为4.51±0.7分钟。结果表明，计算得出的Na⁺转运池位于细胞内。对照条件下的Na⁺转运池为35.6±3.4 nmol/cm²，这对应于细胞内Na⁺浓度为7.9 mM。添加抗利尿激素激活主动Na⁺转运导致Na⁺转运池显著增加，而用氨氯吡咪抑制跨细胞Na⁺转运导致Na⁺转运池减少。此外，随着细胞内Na⁺浓度（Na⁺转运池）增加，主动Na⁺转运沿S形曲线增加。发现Na⁺泵在细胞内Na⁺浓度为12.5 mM时达到半饱和。