Figure 2.

Proton channel currents. (A) Whole cell proton currents from a microglial cell. Voltage-dependent activation of the proton currents are shown. Currents were elicited by pulses from −100 to 40 mV. Inset represents the voltage protocol. (B) Block of the proton currents by 100 µM of extracellular Zn²⁺. (C) Steady-state gating curves (G-V curve) of proton channel and its temperature dependence. The current amplitudes at the peak of the tail currents were plotted as a function of preceding voltages and were normalized. G-V curves were obtained from six cells at 24 and 34°C. The curves were fitted by the Boltzmann function. The V_1/2 values were −32.2 and −30.2 mV for 24 and 34°C. Inset shows a representative current trace for depolarizing pulse to +40 mV, followed by repolarization to 0 mV. The arrow indicates the peak of tail current.