Effect of TEA and 4-AP on the whole-cell current from a glomus cell isolated from 14-day old rat without leak subtraction. In the whole-cell mode, the membrane potential was held at −60 mV, and a ramp voltage applied (−100 mV to +20 mV; 800 ms duration). Pipette solution contained (mM) 140 KCl, 4 mM ATP, 100 µM GTP, 1 MgCl2, 5 EGTA, 10 glucose and 10 HEPES (pH 7.3) and the bath perfusion solution contained (mM) 117 NaCl, 23 NaHCO3, 5 KCl, 1 CaCl2, 1 MgCl2, and 10 glucose (pH 7.3). TEA (10 mM) and 4-AP (2 mM) was applied to the bath solution to block Kv and BK currents. On the upper left corner, current tracings between −65 mV and −20 mV (enclosed by a rectangle) are magnified to show the difference between control (black line) and after TEA/4-AP treatment (gray line). Note that the two currents begin to diverge at approximately −40 mV.