Fig. 10.
α-Dendrotoxin (α-DTX) blocks a noninactivating current in CZ calyces. A: 100 nM α-DTX blocked a component of the outward current in a CZ calyx. The blocked current (Isubtracted) activated rapidly and showed no inactivation. B: I-V plots show current amplitude measured at the end of each 40-ms pulse vs. voltage (same cell as A). The α-DTX-sensitive current activated at potentials more depolarized than −60 mV. C: a single action potential was evoked after injection of a brief hyperpolarizing current in a CZ calyx (left). α-DTX (100 nM) increased the amplitude of the evoked action potential, increased the afterhyperpolarization potential, and resulted in a second spike (right).