Several lines of evidence have suggested that dopamine (DA) neurons in the ventral tegmental area (VTA) use glutamate as a cotransmitter. We used P8 - P19 transgenic mice with fluorescent DA neurons (DAT-YFP mice; see Masson et al., SFN 2001) to guide the preparation of horizontal brain slices (500 µm thick) encompassing the intact DA neuron projection to the n. accumbens (nAcc). Synaptic currents were recorded in nAcc medium-spiny GABAergic neurons with patch electrodes, under GABAA blockade with gabazine and with intracellular QX-314. Focal, extracellular stimulation of the VTA elicited a putative monosynaptic response with a fixed latency of 19.5 ± 0.9 msec and amplitude of 22.1 ± 2.1 pA (n = 17 cells). This was often followed by a barrage of polysynaptic EPSCs with a latency of 147.1 ± 16.6 msec and amplitude 36.5 ± 2.9 pA (n = 8 cells). The fast responses were reduced reversibly by bath application of the D2 agonist quinpirole (10 µM) to 58.8 ± 6.1% (n = 3 cells), arguing that they arise from DA neuro...