Analysis of depolarization-induced outward currents in goat chondrocytes using the patch clamp technique

This study analyzes outward currents in freshly isolated goat chondrocytes patched in the whole cell mode. Capacitance tracings were recorded from the cells by the time domain method. The average capacitance was 6.33 pF +/- 2.15pF (Mean +/- SD, n = 60). The range was 2.7 pF to 11.2 pF. A family of outward currents was seen when the cell was depolarized from -70 mV to +70 mV in 10 mV increments. The current density at +60 mV varied from 125 pA/pF to 2410 pA/pF. The currents were inhibited by 10 mM tetraethylammonium chloride (TEA) and the current-voltage profile suggests that these are voltage gated K+ channels. The currents were also recordable in a chloride-free external solution, thereby proving that these currents are not chloride currents. There was no evidence of voltage-gated sodium channels in these cells.