Fig. 4.
Kinetics of the DA overflow and of the delayed excitatory response evoked by MFB electrical stimulations before and after administration of a D1 antagonist. The DA overflow evoked by MFB electrical stimulations (four pulses at 15 Hz every 20 sec) was electrochemically monitored in 15 distinct rats. The figure shows a representative recording. Notice that DA was quickly eliminated after the last stimulus with a half-life of 74 ± 13 msec (mean ± SD). The delayed excitatory response of 15 single striatal neurons to 20 consecutive stimulations (four pulses at 15 Hz every 20 sec) was then recorded in these animals before and 20 min after administration of the D1 dopaminergic antagonist SCH 23390 (0.5 mg/kg, s.c.). The two peristimulus time histograms shown inb were calculated by averaging the 15 individual histograms in both groups. Error bars represent SEM.Stars indicate statistically significant differences between bin sizes observed before and after SCH 23390 administration (paired t test; p ≤ 0.0004).