Epithelial Na channels and short-term renal response to salt deprivation.

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Frindt G, McNair T, Dahlmann A, Jacobs-Palmer E, Palmer LG

Epithelial Na channels and short-term renal response to salt deprivation.

Am J Physiol Renal Physiol. 2002 Oct;283(4):F717-26.

PubMed ID

12217863 [ View in PubMed

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Abstract

To test the role of epithelial Na channels in the day-to-day regulation of renal Na excretion, rats were infused via osmotic minipumps with the Na channel blocker amiloride at rates that achieved drug concentrations of 2-5 microM in the lumen of the distal nephron. Daily Na excretion rates were unchanged, although amiloride-treated animals tended to excrete more Na in the afternoon and less in the late evening than controls. When the rats were given a low-Na diet, Na excretion rates were elevated in the amiloride-treated group within 4 h and remained higher than controls for at least 48 h. Adrenalectomized animals responded similarly to the low-Na diet. In contrast, rats infused with polythiazide at rates designed to inhibit NaCl transport in the distal tubule were able to conserve Na as well as did the controls. Injection of aldosterone (2 microg/100 g body wt) decreased Na excretion in control animals after a 1-h delay. This effect was largely abolished in amiloride-treated rats. On the basis of quantitative analysis of the results, we conclude that activation of amiloride-sensitive channels by mineralocorticoids accounts for 50-80% of the immediate natriuretic response of the kidney to a reduction in Na intake. Furthermore, the channels are necessary to achieve minimal rates of Na excretion during more chronic Na deprivation.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Polythiazide	Solute carrier family 12 member 3	Protein	Humans	Yes	Inhibitor	Details