Synchronous glucose-dependent [Ca2+](i) oscillations in mouse islets of Langerhans recorded in vivo

Using microfluorescence in combination with image-analysis techniques we mo nitored intracellular calcium ([Ca2+](i)) dynamics in mouse islets of Lange rhans loaded with fura-2 and recorded in vivo. [Ca2+](i) oscillates in the glycaemias range 5-10 mM, the duration of the oscillations being directly p roportional to the blood glucose concentration. The analysis of different a reas within the same islet shows that [Ca2+](i) oscillations are synchronou s 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. (C) 2000 Federation of European Biochemical S ocieties. Published by Elsevier Science B.V. All rights reserved.