Abstract

Background

The most profound effect of vasopressin on the kidney is to increase water reabsorption through V₂-receptor (V₂R) stimulation, but there are also data suggesting effects on calcium transport. To address this issue, we have established an isolated perfused kidney model with accurate pressure control, to directly study the effects of V₂R stimulation on kidney function, isolated from systemic effects.

Methods

The role of V₂R in renal calcium handling was studied in isolated rat kidneys using a new pressure control system that uses a calibration curve to compensate for the internal pressure drop up to the tip of the perfusion cannula.

Results

Kidneys subjected to V₂R stimulation using desmopressin (DDAVP) displayed stable osmolality and calcium reabsorption throughout the experiment, whereas kidneys not administered DDAVP exhibited a simultaneous fall in urine osmolality and calcium reabsorption. Epithelial sodium channel (ENaC) inhibition using amiloride resulted in a marked increase in potassium reabsorption along with decreased sodium reabsorption.

Conclusions

A stable isolated perfused kidney model with computer-controlled pressure regulation was developed, which retained key physiological functions. The preparation responds to pharmacological inhibition of ENaC channels and activation of V₂R. Using the model, the dynamic effects of V₂R stimulation on calcium handling and urine osmolality could be visualised. The study thereby provides evidence for a stimulatory role of V₂R in renal calcium reabsorption.

中文翻译：

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离体灌注大鼠肾脏中的电解质处理：证明血管加压素 V2 受体依赖性钙重吸收。

摘要

背景

加压素对肾脏的最深远影响是通过 V ₂受体 (V ₂ R) 刺激增加水重吸收，但也有数据表明对钙转运的影响。为了解决这个问题，我们建立了一个具有精确压力控制的孤立灌注肾脏模型，以直接研究 V ₂ R 刺激对肾功能的影响，从全身效应中分离出来。

方法

V ₂ R 在肾钙处理中的作用在离体大鼠肾脏中进行了研究，该系统使用一种新的压力控制系统，该系统使用校准曲线来补偿直至灌注套管尖端的内部压降。

结果

使用去氨加压素 (DDAVP)进行 V ₂ R 刺激的肾脏在整个实验过程中表现出稳定的渗透压和钙重吸收，而未施用 DDAVP 的肾脏表现出尿渗透压和钙重吸收同时下降。使用阿米洛利抑制上皮钠通道 (ENaC) 导致钾重吸收显着增加，钠重吸收减少。

结论

开发了一种具有计算机控制压力调节的稳定隔离灌注肾脏模型，该模型保留了关键的生理功能。该制剂对 ENaC 通道的药理学抑制和 V ₂ R 的激活有反应。使用该模型，可以可视化V ₂ R 刺激对钙处理和尿渗透压的动态影响。因此，该研究为 V ₂ R 在肾钙重吸收中的刺激作用提供了证据。