FIG. 3.

Local application of quinpirole to neostriatum (Str) reduced the amplitude of the cortical stimulation-evoked IPSCs in GPe neurons. A: diagram of experimental setup. Quinpirole (10–50 μM in the ACSF, 0.2–0.3 ml/min) was applied through a stainless steel tube (ID ≈ 0.6 mm) that was aimed at the middle of Str. B: examples of IPSCs recorded from a GPe neuron show that quinpirole decreased the amplitude of IPSCs [samples were taken at the time points (a–e) indicated in C]. C: decrease of IPSC amplitude observed during sequential local application of 10, 20, and 50 μM quinpirole for 5 min each. D: summary of the quinpirole effects. Quinpirole with concentrations 10–50 μM all significantly decreased the IPSC amplitudes. Only a partial recovery was observed after a 20-min wash. Paired t-test compared with control (**P < 0.01, ***P < 0.001).