Basolateral P2X4 channels stimulate ENaC activity in Xenopus Cortical Collecting Duct A6 cells.

Basolateral P2X4 channels stimulate ENaC activity in Xenopus Cortical Collecting Duct A6 cells. Am J Physiol Renal Physiol. 2014 Aug 6; Authors: Thai TL, Yu L, Eaton DC, Duke BJ, Al-Khalili OK, Lam HY, Ma H, Bao HF Abstract The polarized nature of epithelial cells allows for different responses to luminal or serosal stimuli. In kidney tubules, ATP is produced luminally in response to changes in luminal flow. Luminal increases in ATP have been previously shown to inhibit the renal epithelial sodium channel (ENaC). On the other hand, ATP is increased basolaterally in renal epithelia in response to aldosterone. We tested the hypothesis that basolateral ATP can stimulate ENaC function through activation of the P2X4 receptor/channel. Using single channel cell attached patch clamp techniques, we demonstrate the existence of a basolaterally expressed channel stimulated by the P2X4 agonist meSATP in Xenopus A6 cells, a renal collecting duct principal cell line. This channel had a similar reversal potential and conductance to that of P2X4 channels. Cell surface biotinylation of the basolateral side of these cells confirmed the basolateral presence of the P2X4 receptor. Basolateral addition of meSATP enhanced the activity of ENaC in single channel patch clamp studies, an effect which was absent in cells transfected with a dominant negative P2X4 receptor construct, indicating that activation of P2X4 channels stimulates ENaC activity in these ce...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research