Fig. 1
Tyramine suppresses IA in TG neurons. a IA isolation. Left panel, exemplary current traces before and after the application of 5 mM 4-aminopyridine (4-AP). Insets, remaining current after off-line subtraction of the noninactivating component of the current remaining after a brief prepulse to − 10 mV. Right panel, summary of results showing the effect of 5 mM 4-AP on IA (n = 11 cells). **p < 0.01 vs. control, paired t test. b Exemplary current traces (left panel) and a bar chart (right panel) indicating that 0.1 µM tyramine selectively decreases IA (n = 9 cells). *p < 0.05 vs. control, paired t test. c, The fitted dose–response curve showing tyramine-induced IA inhibition. The IC50 was calculated from fits of dose–response data to the Hill equation. The numbers of TG neurons recorded at each tyramine concentration are indicated in round brackets. d and e Exemplary traces (d) and current-voltage (I-V) plots (e) of IA in the absence and presence of 0.1 µM tyramine (n = 12 cells). *p < 0.05 vs. control, one-way ANOVA. f bath application of 0.1 µM tyramine did not affect the voltage-dependent activation curve (n = 11 cells) but shifted the steady-state inactivation curve leftward (n = 11 cells). Plots showing voltage-dependent activation and steady-state inactivation were fitted by the Boltzmann equation. g Bar chart summarizing the effect of tyramine on V50 in the activation or inactivation curve. *p < 0.05 vs. control, one-way ANOVA