VOLUME-SENSITIVE CHLORIDE CURRENTS IN PRIMARY CULTURES OF HUMAN FETALVAS-DEFERENS EPITHELIAL-CELLS

Using the patch-clamp technique, we have identified a large, outwardly rectifying, Cl(-)selective whole-cell current in primary cultures of human vas deferens epithelial cells. Whole-cell currents were time- an d voltage-dependent and displayed inactivation following depolarising pulses greater than or equal to 60 mV. Currents were equally permeable to bromide (P-Br/P-Cl = 1.05 +/- 0.04) iodide (P-l/P-Cl - 1.06 +/- 0. 07) and Cl-, but. significantly less permeable to gluconate (P-Gluc/P- Cl = 0.23 +/- 0.03). Currents spontaneously increased with rime after establishing a whole-cell recording but could be inhibited by exposure to a hypertonic bath solution which reduced inward currents by 68 +/- 4%, Subsequent exposure of the cells to a hypotonic bath solution led to a 418 +/- 110% increase in inward current, indicating that these c urrents are regulated by osmolarity, 4,4'-Diisothiocyanatostilbene-2,2 '-disulphonic acid (100 mu M) produced a rapid and reversible voltage- dependent block (60 +/- 5% and 10 +/- 7% inhibition of current, measur ed at +/- 60 mV, respectively). Dideoxyforskolin (50 mu M) also reduce d the volume-sensitive Cl- current, but with a much slower time course , by 41 +/- 13% and 32 +/- 16% (measured at +/- 60 mV, respectively). Tamoxifen (10 mu M) had no effect on the whole-cell Cl- current, These results suggest that vas deferens epithelial cells possess a volume-s ensitive Cl- conductance which has biophysical and pharmacological pro perties broadly similar to volume-sensitive Cl- currents previously de scribed in a variety of cell types.