Fig. 1
From: Structural basis for delta cell paracrine regulation in pancreatic islets
Delta cell activity in vivo. Delta cells are activated by increasing glucose levels. Longitudinal imaging of in vivo activity in islets expressing the Ca2+ reporter GCaMP3 in delta cells. a Maximum projection images a representative mouse (top) and a human islet (bottom) immunostained with anti-glucagon, anti-insulin, and anti-somatostatin antibodies. Cell nuclei are shown in light blue. Graphs on the right show the cellular composition of mouse (n = 24 islets total, n = 7 mice) and human islets (n = 21 islets total, n = 3 donors). b Individual traces from four representative delta cells within a single islet in vivo and showing the profile of spiking and slow delta cells. Insulin (0.25 U/kg) was injected 2 min prior to glucose injection (0.4 g/kg i.v.). Gray-shaded area indicates a predetermined time zone used for data analysis and marks the glucose stimulation period. Basal and recovery periods are located to the left and right of the grey-shaded area, respectively. c Relative distribution (or frequency) of detected peaks in all spiking delta cells analyzed (n = 217) over the course of up to 18 min. Grey-shaded area represents the glucose-stimulated time period as described in b. d Normalized spiking delta cell activity peak amplitude for basal (n = 4574 peaks); glucose (n = 7850 peaks); and recovery (n = 10518 peaks) time periods. In e, same as in d, however the graph shows the breakdown of the normalized peak amplitude in the first or last 2 min of the glucose stimulation time period. f Hierarchical clustering analysis of the spiking delta cell activity under basal, the first or last 2 min of glucose-stimulated or recovery time periods. g Normalized delta cell peak amplitude in nonsynchronized (OFF) and synchronized (ON) peaks. In a, scale bar = 35 µm. Statistics: in c, *p = 0.0001 vs time 0 (d, e, and g) **p < 0.0001, (g) #p < 0.0001 vs respective OFF group. All comparisons made with OneWay Anova with a Tukey multiple comparison test. Error bars represent the 95% confidence interval (C.I.) of the mean. For a, c–e, and g, source data are provided as a Source Data file
