Figure 5.

Serotonin receptor 5-HT1B agonist CP-93129 lowers the average IPSC amplitude and synaptic success rate. A, Example IPSC amplitude recording and drug treatment for D1→D2-SPN connections (D1-Cre mouse). Bath application of serotonin receptor 5-HT1B agonist CP-93129 results in silencing of IPSCs. Recording of IPSCs resumes after washout. B, Example IPSC amplitude recording and drug treatment for D2→D1-SPN connections (A2a-Cre mouse). Bath application of serotonin receptor 5-HT1B agonist CP-93129 results in reduction of IPSCs amplitude and increased failures. IPSC recording recovers after washout. C, E, G, Average IPSC amplitude change during drug treatment for D2 SPNs (N = 12, D1-Cre mice; C), D1-SPNs (N = 6, A2a-Cre mice; E) and control conditions [N = 6: D1-Cre (3), A2a-Cre (3); G)]. Each point is an average of six IPSC events. Dotted lines represent SEM IPSC amplitude change was normalized against last 5 min of baseline. The traces on the right are examples recorded during baseline (black), drug treatment/equal period for control conditions (light gray) and washout (dark gray). The black bar represents the 2-ms light pulse. D, F, H, Average group synaptic success rate of D1→D2-SPNs (D), D2→D1-SPNs (F), and control conditions (H). Individual synaptic success rate was calculated as number of recorded IPSCs per minute divided by the number of maximal IPSCs per minute. D, F, H, same cells as C, E, G. Dotted lines represent SEM. All recordings were done in the presence of KA.