Extended Data Fig. 1: Visualization of zinc flickers by spinning-disc confocal microscopy.
a, Schematic diagram of imaging Zn2+/insulin corelease (‘Zinc flicker’) with spinning-disc confocal microscope. The islet was seeded on a glass coverslip, and only a thin region above the glass coverslip (∼1 μm) was imaged. b, Typical images of fusion events in the islet (from a male mouse) before and after stimulation with 18.2 mM glucose for 3 min. White puncta represented fused insulin granules labeled with fluorescent FluoZin-1. c, Dynamic insulin secretion evoked by 20 mM glucose with or without FluoZin-1 dye as determined by ELISA. Data were quantified from four independent experiments from male mice. d, Representative images of secretion (all fusion events in 15 minutes) in islets (from male mice) exposed to 11 mM glucose, either in the absence (Control) or presence of 250 µM diazoxide (Diazoxide). e, Averaged fusion events stimulated by 11 mM glucose (Control, n = 6 islets from 3 male mice) or with 250 μM diazoxide (Diazoxide, n = 5 islets from 3 male mice). f, Fusion events before (Diazoxide) and after (glucose) removal of diazoxide treatment on the same islet. n = 3 islets from 2 male mice. Significance was evaluated by ratio paired t test. g, Averaged fusion events detected in α-cells (n = 45 cells from 10 male islets) and δ−cells (n = 45 cells from 11 islets, mixed from male and female mice). h-i, Representative images of secretion (15 minutes) in male Glu-GCaMP (h) and Stdt islets (i) exposed to 18.2 mM glucose. White and cyan circles represented α and δ cells respectively. Cell membrane was coded by mpl-inferno color. Data was expressed as mean ± s.e.m. in c, e, g, and analyzed by two-sided unpaired Student t-test, * p < 0.05, ** p < 0.01. Scale bar = 10 μm.
