Fig. 11: Metabotropic GABA receptors are functional in CSF-cNs and inhibit calcium channels.
A Representative ICa traces elicited at the current peak with a voltage step to +10 mV from Vh -80 mV and recorded in CSF-cNs from the C (A1), T (A2) and L segments (A3) in control (black traces), in response to baclofen alone (baclofen; Left, colored traces) or in the presence of CGP (+ CGP, 2 μM; Right, violet traces) and after agonist Wash (gray traces). B Average time courses of normalized ICa peak amplitude recorded in CSF-cNs for the regions of interest (B1, C: N = 2, 3; n = 9, 11; B2, T: N = 3, n = 9, 6 and B3, L: N = 3, n = 11, 9) in control and in the presence of CGP. Baclofen was applied at 100 μM by pressure for 40 s (+ Bcl, black bar). C Summary plots for the normalized peak ICa density (mean ± SD) before (CTR), during (Bcl) and after agonist application (Wash) in the absence (Left) or presence of CGP (Right, in CGP, violet bar) for the regions of interest (Bcl alone, C: N = 2, n = 9; T: N = 3, n = 9 and L: N = 3, n = 11. Bcl in CGP: C: N = 3, n = 11; T: N = 3, n = 6 and L: N = 3, n = 9). Friedman test for Bcl alone: χ2(Bcl)=14.2, 16.2 and 18.7, df = 2, p(χ2) = 8.16 × 10−5, 3.00 × 10−5 and 8.58 × 10−6 for C, T and L segments and post hoc Pairwise comparisons using Wilcoxon rank sum test with Benjamini-Hochberg adjustment to compare currents densities within Regions for CTR vs. Bcl and Bcl vs. Wash: p = 0.012, 0.006 and 0.001/0.01. Friedman test for Bcl in CGP: χ2(CGP) = 1.27, 5.33 and 2.00, df = 2, p(χ2) = 0.529, 0.069 and 0.368 for C, T and L segments and post hoc pairwise comparisons using Wilcoxon rank sum test with Benjamini-Hochberg adjustment to compare currents densities within regions for CTR vs. Bcl and Bcl vs. Wash: p = 0.898, 0.328/0.438 and 0.652 for C, T, and L. D Summary boxplots for the ICa inhibition induced during (Bcl) and after (Wash) agonist application and in the absence (Left) and presence of CGP (Right; in CGP, violet bar) for the 3 regions of interest (Bcl alone, C: N = 2, n = 9; T: N = 3, n = 9 and L: N = 3, n = 11. Bcl in CGP, C: N = 3, n = 1; T: N = 3, n = 6 and L: N = 3, n = 9. Kruskal-Wallis rank sum test: χ2(Bcl)=31.082, df=1, p(χ2) = 2.473 × 10−8 and post hoc pairwise comparisons using Wilcoxon rank sum test with continuity correction: Bcl vs. Wash: p = 5.7 × 10−10; χ2(Region)=1.0398, df=2, p(χ2) = 0.5946 and post hoc pairwise comparisons using Wilcoxon rank sum test with continuity correction: p = 0.62 for C vs. L, C vs. T and T vs. L, respectively. Kruskal-Wallis rank sum test: χ2(CGP) = 0.90566, df = 1, p(χ2) = 0.3413 and post hoc pairwise comparisons using Wilcoxon rank sum test with continuity correction: Bcl in CGP vs. Wash: p = 0.35; χ2(Region)=5.742, df = 2, p(χ2) = 0.05664 and post hoc pairwise comparisons using Wilcoxon rank sum test with continuity correction: p = 0.411for C vs. L and p = 0.072 for C vs. T and T vs. L, respectively. In B: colored open circles: in control; violet filled circles: in the presence of CGP. mean ± SD; with SD represented as colored shaded area. In C large filled colored circles: mean ± SD; small open and filled colored circles: single data points for all the recorded cells at each level. Data are given in the CTR, Bcl and Wash order. In D, Data are given in Bcl and Wash order.
