Concentration-dependent effects of VSCC inhibitors (A), PK inhibitors (B), PK activators (C), and BoNTs (D) on hippocampal basal serotonin release. The ordinates indicate the mean ± SD (n = 6) of area under the curve (AUC) values of extracellular serotonin level (fmol/10 μl), and abscissas show the concentration of VSCC inhibitors, PK inhibitors, and PK activators (log μm), or the dose of BoNTs (log ng). A–C, To study the effects of VSCC inhibitors, PK inhibitors, and PK activators on basal serotonin release, the perfusion medium was switched from MRS to MRS containing GVIA, IVA, H-89, CHR, PMA, or forskolin for 120 min. The mean values obtained by perfusion without (Control) and with each agent were compared by one-way ANOVA and Tukey's multiple comparison test (*p < 0.05, **p < 0.01).D, To compare the effects of BoNTs on basal serotonin release, the microinfusion of BoNT/B and BoNT/C is shown. The mean values obtained by microinfusion without (Control) and with BoNTs were compared by one-way ANOVA and Tukey's multiple comparison test (*p < 0.05, **p < 0.01).