Effects of glucose on [Ca2+]c oscillations in primary mouse α-cells expressing the ratiometric pericam under the control of the PPG promoter. A: Immunocytochemistry performed in dispersed mouse islet cells. The left panels illustrate bright field, the middle panels illustrate the GFP (green fluorescent protein) fluorescence of the ratiometric pericam (excited at 480 nm), and the right panels illustrate glucagon immunoreactivity. B–D: [Ca2+]c oscillations in three distinct single α-cells. Glucose concentration (G) was reduced from 20 to 0.5 mmol/l, and 30 mmol/l
K+ (K30) was applied as indicated. Arrows 1 and 2 in panel B indicate time points of image 1 and 2. Arb., arbitrary.