A, the amplitudes of OCPs increased in 1-EBIO (200 μm). OCPs were recorded in control (Aa) and during 1-EBIO application (Ab). The periods for sampling these OCPs are indicated by horizontal lines underneath the trace in B. B, same cell as in A. Each upstroke is one OCP in this continuous recording. C, 1-EBIO markedly increased the area enveloped by a single OCP in GABAergic SNr neurons. There was little effect on amplitude, frequency was not changed. In DA neurons, which were recorded for comparison, the enlargement of the area was much less striking. OCPs occurring during 90 s were averaged, and the average in control normalized to 1 (n = 9 GABA cells and 6 DA cells, respectively). *P < 0.01.