Figure 6. Co-application with the D₄ antagonist L745870 (10 µM) enabled 60 µM SKF38393 to enhance LTP.

A) Summary plot of normalized fEPSP measurements. Open circles show normalized fEPSP slope from slices treated with L745870 (10 µM); closed circles depict slices treated with SKF38393 (60 µM); closed triangles depict slices treated with both L745870 (10 µM) and SKF38393 (60 µM). Insets are 50 ms sweeps averaged from all experiments illustrating the mean fEPSP 1–5 min prior to and 26–30 min post-tetanus (vertical scale bar is 3 mV). The left pair of sweeps (1) is from SKF38393-treated slices, the right upper pair (2) is from L745870 & SKF38393-treated slices, the right lower pair (3) is from L745870-treated slices. B) Summary quantification of LTP magnitude in the presence of SKF38393 alone, when L745870 is co-applied with SKF38393, and when L745870 is applied alone (significance relative to the control group indicated by the dashed line, **p < 0.01; significance relative to the L745870 group is also indicated, †p < 0.05). Error bars show ± SEM.