Fig. 6

SWELL1-mediated I_Cl,SWELL and I_KATP coordinately regulate β-cell excitability. a GCaMP6s Ca²⁺ transients in WT (Ad-RIP1-GCaMP6s/Swell1^fl/fl) primary murine β-cells in response to 16.7 mM 3-O-Methyl-glucose-stimulation (basal 1 mM glucose) and 40 mM KCl stimulation. 3-O-Methyl-glucose fail to induce Ca²⁺ transients (n = 15 cells). b–e Glucose-induced Ca²⁺ transients are inhibited in WT MIN6 cells (b, c) and in WT primary murine β-cells (d, e) by bumetanide (10 µM; pre-incubated in bumetanide for 2 h). c Mean peak Fura-2 ratio from bumetanide-treated WT MIN6 cells (n = 46 cells). d Mean peak values of GCaMP6s Ca²⁺ transients from bumetanide-treated WT primary murine β-cells (n = 7 cells). f, g In the presence of K_ATP channel opener, diazoxide (100 µM), glucose-induced Ca²⁺ transients are abolished in WT primary murine β-cells. g Mean peak values of GCaMP6s Ca²⁺ transients from WT primary murine β-cells treated with diazoxide (n = 17 cells). h–j Low-dose glibenclamide (0.25 nM, 0 mM glucose), which is predicted to block a fraction of K_ATP channels, reproducibly induced Ca²⁺ transients in WT (h), but not Swell1 KO (i) primary murine β-cells. j Mean peak values of GCaMP6s Ca²⁺ transients stimulated by 0.25 nM glibenclamide in WT β-cells (n = 19 cells) and Swell1 KO β-cells (n = 8 cells), and KCl-positive controls. k–m High-dose glibenclamide (10 nM), which has a maximal inhibitory effect on K_ATP channels, activated Ca²⁺ transients in both WT (k) and Swell1 KO β-cells (l). m Mean peak values of GCaMP6s Ca²⁺ transients stimulated by 10 nM glibenclamide in WT β-cells (n = 4 cells) and Swell1 KO β-cells (n = 4 cells). Data are shown as mean ± s.e.m. One-way ANOVA for in-group comparison, unpaired t-test for between-group comparison. *p < 0.05, **p < 0.01, ***p < 0.001. ns, not significant