Synchronous glucose-dependent [Ca(2+)](i) oscillations in mouse pancreatic islets of Langerhans recorded in vivo.

Using microfluorescence in combination with image-analysis techniques we monitored intracellular calcium (Ca(2+)) dynamics in mouse islets of Langerhans loaded with fura-2 and recorded in vivo. Ca(2+) oscillates in the glycaemias range 5-10 mM, the duration of the oscillations being directly proportional to the blood glucose concentration. The analysis of different areas within the same islet shows that Ca(2+) oscillations are synchronous throughout the islet. These results show that in vivo, individual islets of Langerhans behave as a functional syncytium and suggest the existence of secretory pulses of insulin.