Glucose-stimulated Single Pancreatic Islets Sustain Increased Cytosolic ATP Levels during Initial Ca2+Influx and Subsequent Ca2+Oscillations

摘要: In pancreatic islets, insulin secretion occurs via synchronous elevation of Ca2+ levels throughout the islets during high glucose conditions. This has two phases: a quick increase, observed after stimulus, followed by prolonged oscillations. these processes, intracellular ATP generated from is assumed to inhibit ATP-sensitive K+ channels, leading depolarization membranes, which in turn induces islets. However, little known about dynamics and their correlation with response changing levels. this study, genetically encoded fluorescent biosensor for dye were employed simultaneously monitor levels, respectively, inside single isolated We rapid increases cytosolic mitochondrial stimulation glucose, as well methyl pyruvate or leucine/glutamine. High sustained long persisted. Inhibition production suppressed initial suggesting that enhanced energy metabolism triggers phase influx. On other hand, did not fluctuate significantly level subsequent oscillation phases. Importantly, oscillations stopped immediately before decreased significantly. These results might explain how food intake evokes resulting decrease plasma leads cessation secretion.