Figure 1. Dopamine inhibits the GABA_B IPSP.

A, example of the concentration-dependent and reversible inhibition caused by DA in the slow IPSP which was subsequently reduced by the GABA_B receptor antagonist CGP (300 nm). B, time course of DA effects. Here and in subsequent graphs, the amplitudes of the IPSPs were normalized to the control amplitude determined for at least 5 min before application of DA. Each data point in this graph represents the mean ± s.e.m. of 7 cells. C, concentration-dependent curve of the reducing effects of DA on the GABA_B-mediated IPSP. Each point represents the mean ± s.e.m. of 25 cells.