Pancreatic β cells exhibit oscillations in electrical activity, cytoplasmic free Ca2+ concentration ([Ca2+]i), and insulin release upon glucose stimulation. The mechanism by which these oscillations are generated is not known. Here we demonstrate fluctuations in the activity of the ATP-dependent K+ channels (KATP channels) in single β cells subject to glucose stimulation or to stimulation with low concentrations of tolbutamide. During stimulation with glucose or low concentrations of tolbutamide, KATP channel activity decreased and action potentials ensued. After 2-3 min, despite continuous stimulation, action potentials subsided and openings of KATP channels could again be observed. Transient suppression of metabolism by azide in glucose-stimulated β cells caused reversible termination of electrical activity, mimicking the spontaneous changes observed with continuous glucose stimulation. Thus, oscillations in KATP channel activity during continuous glucose stimulation result in oscillations in electrical activity and [Ca2+]i.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - May 14 1996|
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