Figure 1

VGCC currents in Bushy neurons. (a) Whole-cell currents recorded from a bushy neuron in AVCN. The cell was held at −80 mV and hyperpolarizing to −100 mV before depolarizing to various test potentials from −100 to + 40 mV in 10 mV increment at 5 sec intervals. (b) Current-voltage relationships for data in A measured at the peak current amplitudes showed both LVA and HVA VGCC currents. The peak inward current activated positive to about –70 mV and peaked at about –10 mV. Charge carrier, 5 mM Ba²⁺. (c) Correlation between the age and the total VGCC current density in bushy neurons. Bushy neurons were divided into three age groups (P4-6, black circles; P8-12, magenta circles; P15-17, orange circles). (d) Developmental changes in VGCC current in bushy neurons. The cells were bathed in 5 mM external barium. The extent of inhibition by Mibefradil (1 µM; black bars; n = 20), nifedipine (10 µM; green bars; n = 20), ω-CTx GVIA (1 µM; red bars; n = 25), ω-Aga IVA (500 nM; blue bars; n = 22) and NiCl₂ (50 µM; cyan bars; n = 22) was quantified and compared to show the contribution of each antagonist-sensitive calcium channels in three age groups (P4-P6, P8-P12 and P15-P17). Five One-way ANOVA tests were further used to determine whether there were any significant differences between the fraction of each subtype current in three age groups. **P < 0.01, ns, not significant, two-way ANOVA with Bonferroni post hoc test.