Figure 2.

Effects of Ca²⁺ channel inhibitors on peak and trough Ca²⁺ concentration. (A and B) Time course of the change in Ca²⁺ concentration (ΔCa²⁺ = Ca²⁺ − average Ca²⁺ from 2-min baseline) before and after the application of vehicle control (Veh) or Ca²⁺ channel inhibitors at the peak (A) and trough (B). Data are mean ± SEM. (C and D) Plots of median, 25th and 75th percentile (boxes), and minimal and maximal (whiskers) changes in Ca²⁺ concentration for individual slices quantified from 9 to 10 min after drugs were applied at the peak (C) and trough (D). Inhibition of L-type Ca²⁺ channels with nimodipine (Nim, 10 μM) or inhibition of N/P/Q/R/T-type Ca²⁺ channels with VGC (a mixture of 3 μM ConoGVIA, 200 nM AgaIVA, 30 μM nickel, and 1 μM TTA-P2) did not significantly affect peak or trough Ca²⁺ levels compared to Veh. Inhibition of ryanodine receptors with dantrolene (Dan, 10 μM), inhibition of SERCA-ATPase with cyclopiazonic acid (CPA, 10 μM) and combined inhibition of voltage-gated Ca²⁺ channels and ryanodine receptors with a cocktail containing Dan, Nim, and VGC (cocktail X) significantly decreased Ca²⁺ at peak and trough. ∗p < 0.05, one-way ANOVA and Bonferroni post hoc test between drug and vehicle control conditions at peak (Nim, p = 0.3; VGC, p = 0.1; Dan, p = 0.02; CPA, p = 0.005; X, p = 0.003) and trough (Nim, p = 0.4; VGC, p = 1; Dan, p = 0.0004; CPA, p = 0.02; X, p = 0.002). Post hoc values were p > 0.05 for all other comparisons. Data points represent average measurements from individual SCN slices (one imaging region per slice). N = 4–11 slices per condition.