Effects of 5-HT on sIPSCs recorded at the holding potential of 0 mV. (A) Bath applied 5-HT (50 μM) increased a frequency but not amplitude of sIPSCs in 58% of SG neurons. Lower traces show sIPSCs before (left) and after (right) the application of 5-HT in the expanded time scale. (B) cumulative sIPSCs of the inter-event interval (**P < 0.01, K-S test) and amplitude (C, P > 0.05, K-S test) distributions recorded in control and in the presence of 5-HT. (D) shows the relative frequency and amplitude compared with the pre-application levels (n = 98). (E) 5-HT (50 μM) increased the frequency and amplitudes of sIPSCs in 23% of SG neurons. Lower typical traces of sIPSCs observed before, during application of 5-HT. (F) Cumulative probability of the inter-event interval and amplitude (G) of sIPSCs for the neuron in (E). Both distributions of amplitude and frequency during 5-HT were significantly different from the control (***P < 0.001 and **P < 0.01, respectively, K-S test). (H) The bar graph normalized results of the frequency and amplitude with the control (n = 36).