Fig. 2. Depolarization-activated inward currents in the pharynx. (A) Total inward currents in the wild type (WT) and in the cca-1 mutant. (B) High voltage-activated (HVA) currents in the WT and in cca-1. In these experiments the low voltage-activated (LVA) current was inactivated with a 300 ms prepulse to -40 mV. (C) Ni²⁺ (2 mmol l^-1) blocks both the LVA and the HVA currents. (D) Nifedipine (10 µmol l^-1) blocks the HVA, but not the LVA current. Recordings in C and D are from wild-type pharynxes, and the pulse protocol is the same as in A. Numbers next to current traces indicate peak depolarization of the voltage pulse.