Fig. 2.

Voltage-dependent relief of block seen for GVIA, MVIIA, TVIA, and MVIIC. GVIA (A), MVIIA (B), TVIA (C), and MVIIC (D) (all at 5 μm) were applied to oocytes expressing the N-type Ca²⁺ channels initially held at −80 mV. After 7 min of toxin application, washout at the same HP gave very little recovery of current. After an initial 7 min of washout at −80 mV, the HP of the oocyte was stepped to −120 mV, which evoked a more rapid rate of current recovery. After what appeared to be complete recovery of current, a second application of toxin was given to ensure that this recovered current was still sensitive to block. Results illustrate behavior observed in multiple oocytes (n = 3 for each toxin).