Fig. 7.

Evoked and delayed release in the presence of the nicotinic ACh receptor antagonist, dihydro beta erythroidine (DHβE). A: average and standard deviation of membrane current evoked by a train of 10 shocks at 40 Hz. The evoked response facilitates and summates throughout the train and is followed by a slow decay (“tail current”) that includes delayed synaptic events (less visible in this averaged record). B: the standard deviation of the tail current was integrated from the end of the shock train for the next 1.5 s to quantify delayed release. Delayed release was reduced by exposure to 100 nM DHβE (n = 4) and recovered partially after washout.