A: Representative current-clamp trace showing the lack of an AF2 potentiated secondary response following replacement of calcium with cobalt APF-Ringer following the end of levamisole application (1 μM).
B: Bar graph comparing mean durations of secondary depolarizations, T80, from different preparations recorded after AF2 treatment in the presence and absence of calcium (calcium replaced using cobalt APF-Ringer). Calcium substitution caused a significant reduction in the duration of the secondary response (p < 0.001, n = 4, unpaired t-test).