Oscillations in KATP channel activity promote oscillations in cytoplasmic free Ca2+ concentration in the pancreatic beta cell.
- 14 May 1996
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 93 (10), 5161-5165
- https://doi.org/10.1073/pnas.93.10.5161
Abstract
Pancreatic beta 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 (K(ATP) channels) in single beta cells subject to glucose stimulation or to stimulation with low concentrations of tolbutamide. During stimulation with glucose or low concentrations of tolbutamide, K(ATP) channel activity decreased and action potentials ensued. After 2-3 min, despite continuous stimulation, action potentials subsided and openings of K(ATP) channels could again be observed. Transient suppression of metabolism by azide in glucose-stimulated beta cells caused reversible termination of electrical activity, mimicking the spontaneous changes observed with continuous glucose stimulation. Thus, oscillations in K(ATP) channel activity during continuous glucose stimulation result in oscillations in electrical activity and [Ca2+](i).Keywords
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