Effects of VSCC inhibitors (A), PK inhibitors (B), PK activators (C), and BoNTs (D) on hippocampal K⁺-evoked serotonin release. The ordinates indicate the mean ± SD (n = 6) of extracellular serotonin level (fmol/10 μl), and abscissas show the time in minutes. The open barsindicate perfusion with VSCC inhibitors, PK inhibitors, and PK activators, and striped bars indicate K⁺-evoked stimulation for 20 min.A–C, To study the effects of VSCC inhibitors, PK inhibitors, and PK activators on K⁺-evoked serotonin release, the perfusion medium was switched from MRS containing GVIA (1 μm), IVA (1 μm), H-89 (1 μm), CHR (1 μm), PMA (10 μm), or forskolin (10 μm) to HKMRS containing the same agents for 20 min. D, To compare the effects of BoNTs on K⁺-evoked serotonin release, the microinfusion of 0.3 ng of BoNT/A, BoNT/B, or BoNT/C is shown. The mean values obtained before and after K⁺-evoked stimulation were compared using repeated-measure one-way ANOVA and Dunnett's multiple comparison test.