Fig. 6.

Muscimol-induced presynaptic depolarization activates high-threshold VDCCs. A, Typicaltraces of sEPSCs observed before, during, and after application of 0.5 μm muscimol in the control solution (a) and in the presence of 3 μmω-CgTx, 0.3 μm ω-AgTx, and 3 μmnicardipine (b). B, Cumulative distributions of interevent intervals (a;p = 0.399) and current amplitudes (b; p = 0.165) in the same neuron shown in A (436 events for the control, 233 events for VDCC antagonists, and 83 events for muscimol). C, The mean sEPSC frequency (a) and amplitude (b) of five neurons. All columnswere normalized to the control (dotted lines).