Glucose increases activity and Ca2+ in insulin-producing cells of adult Drosophila.

We sought to understand the mechanisms underlying glucose sensing in Drosophila melanogaster. We found that insulin-producing cells (IPCs) of adult Drosophila respond to glucose and glibenclamide with a burst-like pattern of activity. Under controlled conditions IPCs have a resting membrane potential of -62+/-4 mV. In response to glucose or glibenclamide, IPCs generate action potentials at a threshold of -36+/-1.4 mV with an amplitude of 46+/-4 mV and width of 9.3+/-1.8 ms. Real-time Ca imaging confirms that IPCs respond to glucose and glibenclamide with increased intracellular Ca. These results provide the first detailed characterization of electrical properties of IPCs of adult Drosophila and suggest that these cells sense glucose by a mechanism similar to mammalian pancreatic β cells.