FIGURE 1.
Glutamate-mediated synaptic currents recorded in isolated dopamine neurons in vitro. In an isolated neuron, subsequently shown to be TH-positive, a large autaptic EPSC was recorded under voltage clamp. This was almost completely blocked by CNQX (EPSC was 4% of control; traces shown are averages of 10 stimulations; traces during drug application are shown in gray). The reversible D2 antagonist sulpiride enhanced the EPSC (117%; shown here and in subsequent traces without the initiating action current), whereas the D2 agonist quinpirole markedly attenuated the autaptic EPSC (76%). This suggests that concomitant DA release modulates the glutamate-mediated EPSC.