A, example traces of reversible inhibition of Kv3.1aHA currents by 1 mm zinc. Kv3.1aHA was expressed in HEK293 cells. Voltage-clamp recording was performed one day after transfection. B, reversible inhibition of Kv3.1bHA currents by 1 mm zinc. C, reversible inhibition of Kv3.1bHAH77A currents by zinc. D, inhibitory effect of Zn2+ on current amplitude. The number of neurons are indicated within parentheses, and are the same in E–G. E, effects of zinc on G–V curves of Kv3.1aHA and Kv3.1bHA. F, effects of zinc on activation time constant (τon) of three Kv3.1 constructs. G, effects of zinc on deactivation time constant (τoff) of Kv3.1aHA and Kv3.1bHA. Paired t test: **P < 0.01; *P < 0.05.