Elsevier

Kidney International

Volume 58, Issue 5, November 2000, Pages 1893-1901
Kidney International

Hormones – Cytokines – Signaling
Axial distribution and characterization of basolateral P2Y receptors along the rat renal tubule

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Axial distribution and characterization of basolateral P2Y receptors along the rat renal tubule.

Background

Several groups have identified P2Y receptors in the basolateral membrane of the rat nephron. These studies have not covered all segments of the nephron and have relied solely on the relative potency of receptor agonists for classification.

Methods

We measured purine and pyrimidine-induced changes in intracellular free calcium concentration ([Ca2+]i) in anatomically defined segments of the rat nephron. To complement these functional studies, we have used reverse transcription-polymerase chain reaction methodology to identify specific P2Y receptor transcripts in these segments.

Results

Adenosine 5′-triphosphate (ATP) mobilized [Ca2+]i in all nephron segments, except for the thick ascending limb of Henle, which was poorly responsive. Adenosine (100 μmol/L) was without effect, confirming that the effect of ATP was mediated by P2 receptors. In the proximal convoluted tubule (PCT) and outer medullary collecting duct (OMCD), there was evidence for two receptor subtypes with characteristics of P2Y1- and either P2Y2- or P2Y4-like receptors. A novel finding in the thin limbs was the presence of a receptor with properties of both P2Y2 and P2Y4 receptor subtypes. To aid classification, we identified P2Y receptor mRNA in rat nephron segments. In the PCT and OMCD and thin ascending limb of Henle, we found expression of P2Y1, P2Y2, and P2Y4 receptors. In the descending limb of Henle, P2Y1 and P2Y2 mRNA was found, but P2Y4 was not expressed.

Conclusion

These data suggest that extracellular ATP can influence tubular cell function in all segments of the rat nephron, through P2Y receptors via multiple (and coexpressed) P2Y receptor subtypes.

Keywords

purinoceptors
adenosine 5′-triphosphate
thin limb of Henle
intracellular free calcium concentration
receptor agonists
G protein-coupled receptors

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