Fig. 4.
Hypotonicity-induced depolarization of β-cells. Gramicidin-perforated patch-clamp recordings of primary mouse β-cells. a Resting membrane potential of control Lrrc8alox/lox or βc-Δ8a β-cells at 1 or 5 mM glucose concentrations. Mean values ± SEM indicated by error bars. b Representative trace for hypotonicity-induced depolarization of the membrane potential Vm in control Lrrc8alox/lox animals at 5 mM glucose. TOLB, tolbutamide. c ΔVm after applying hypotonicity, or following washout with isotonic solution of Lrrc8alox/lox or βc-Δ8a cells at 5 mM glucose, calculated from data as indicated in b. Spiking cells (see g and h) were excluded from analysis. d Representative voltage trace showing lack of hypotonicity-induced depolarization of βc-Δ8a β-cells at 5 mM glucose. e ΔVm of Lrrc8alox/lox or βc-Δ8a cells as in c, but at 1 mM glucose. f Representative trace for Lrrc8alox/lox β-cells challenged with hypotonicity in the presence of 1 mM glucose. g Percentage of cells responding with electrical activation following hypotonic stimulation. h Voltage trace of an Lrrc8alox/lox β-cell responding with electrical activity to hypotonicity in the presence of 5 mM glucose. *p < 0.05, **p < 0.01 (one-way ANOVA, Tukey’s test)