Whole-cell outward currents in freshly dissociated rat placental cells

1. We applied whole cell voltage clamp techniques to freshly dissociated rat placental cells (20-21 days gestation). Tetraethylammonium (TEA)-sensitive outward currents were recorded in about 50% of cells. 2. The outward current had a reversal potential of -50 mV which is more positive than the potassium equilibrium potential (-82 mV). 3. The bath solution without NaCl decreased the outward current amplitude, while the elimination of only Na ions from the bath solution did not modify the outward current. 4. The results suggest a possible contribution of chloride ions to the outward currents in rat placental cells.