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PubMed · 10484326

Separate taurine and chloride efflux pathways activated during regulatory volume decrease.

A Stutzin·R Torres·M Oporto·P Pacheco·A L Eguiguren·L P Cid·F V Sepúlveda
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Abstract

Organic osmolyte and halide permeability pathways activated in epithelial HeLa cells by cell swelling were studied by radiotracer efflux techniques and single-cell volume measurements. The replacement of extracellular Cl- by anions that are more permeant through the volume-activated Cl- channel, as indicated by electrophysiological measurements, significantly decreased taurine efflux. In the presence of less-permeant anions, an increase in taurine efflux was observed. Simultaneous measurement of the 125I, used as a tracer for Cl-, and [3H]taurine efflux showed that the time courses for the two effluxes differed. In Cl--rich medium the increase in I- efflux was transient, whereas that for taurine was sustained. Osmosensitive Cl- conductance, assessed by measuring changes in cell volume, increased rapidly after hypotonic shock. The influx of taurine was able to counteract Cl- conductance-dependent cell shrinkage but only approximately 4 min after triggering cell swelling. This taurine-induced effect was blocked by DIDS. Differences in anion sensitivity, the time course of activation, and sensitivity to DIDS suggest that the main cell swelling-activated permeability pathways for taurine and Cl- are separate.

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AnionsCell Membrane PermeabilityChloridesElectrophysiologyExtracellular SpaceHeLa CellsHumansTaurineTime FactorsJournal ArticleResearch Support, Non-U.S. Gov't

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A Stutzin, R Torres, M Oporto, P Pacheco, A L Eguiguren, L P Cid, F V Sepúlveda. 1999. Separate taurine and chloride efflux pathways activated during regulatory volume decrease.. https://doi.org/10.1152/ajpcell.1999.277.3.c392

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