Representative time plots of ONO-AE-248 inhibition of peak ICa in a Type 1 (Aa) and Type 2 (Ba) neuron. ICa was elicited by stepping the membrane potential from −80 to 0 mV. Example traces from the Type 1 neuron (Ab) and Type 2 (Bb) neurons are shown in Aa and Ba. C, the inhibition of ICa by ONO-AE-248 in Type 1 (triangles) and Type 2 (squares) neurons was concentration dependent, with an EC50 of 580 nm and 1.4 μm, respectively. Each point represents the mean and s.e.m. of 6–10 cells. D, overnight treatment with PTX (100 ng ml−1) strongly reduced the ONO-AE-248 (10 μm) inhibition of ICa in Type 2 but not Type 1 cells, whereas treatment with CTX (250 ng ml−1) overnight blocked the ONO-AE-248 inhibition of ICa in Type 1 but not Type 2 cells (n = 6–15 for each).