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 Ca2+ imaging confirms that IPCs respond to glucose and glibenclamide with increased intracellular Ca2+. 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 beta cells. NeuroReport 21:1116-1120 (C) 2010 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.