Fig. 2. Summary ketamine dose–response relations for cardiac parasympathetic neurons (n = 9). The nicotine-evoked inward current (normalized to control, A ) was inhibited by increasing concentrations of ketamine, and this inhibition was statistically significant at a ketamine concentration of 10 μm. Ketamine also significantly (P < 0.05) inhibited the nicotine-evoked increase in miniature glutamatergic synaptic event (mini) amplitude (B ), and this inhibition was significant at a ketamine concentration of 10 μm. Ketamine, at all concentrations examined (0.1–10 μm), had no significant effect on mini amplitude (C ).