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  • Title: Generation of glucose-dependent slow oscillations of cytoplasmic Ca2+ in individual pancreatic beta cells.
    Author: Gylfe E, Grapengiesser E, Liu YJ, Dryselius S, Tengholm A, Eberhardson M.
    Journal: Diabetes Metab; 1998 Feb; 24(1):25-9. PubMed ID: 9534005.
    Abstract:
    Individual pancreatic beta cells respond to glucose stimulation with large amplitude (300-500 nM) oscillations in the cytoplasmic Ca2+ concentration ([Ca2+]i). These oscillations (frequency 0.05-0.5/min) depend on rhythmical depolarization of the plasma membrane, with influx of Ca2+ through voltage-operated channels, but do not require intracellular mobilization of Ca2+. Patch clamp analyses of the activity of ATP-sensitive K+ channels indicate that oscillations in beta-cell metabolism underlie the rhythmical depolarizations, causing the large amplitude oscillations of [Ca2+]. The oscillatory responses of adjacent beta cells are synchronized by gap-junctional coupling in cellular microdomains. With increasing glucose concentration, previously unresponsive domains are activated, and their oscillations entrained with those of other active domains. In pancreatic islets, glucose-induced large amplitude oscillations occur in parallel with insulin release pulses, the amplitudes of which are determined by the number of beta cells recruited into the secretory state.
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