Generation of glucose-dependent slow oscillations of cytoplasmic Ca2+ in individual pancreatic beta cells.
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.
Gylfe
E
E
Grapengiesser
E
E
Liu
Y J
YJ
Dryselius
S
S
Tengholm
A
A
Eberhardson
M
M
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003593:Cytoplasm / Q000187:drug effects* / Q000378:metabolism; D005947:Glucose / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D009991:Oscillometry; D012636:Secretory Rate / Q000187:drug effects; D013268:Stimulation, Chemical
D007328:Insulin; D005947:Glucose; D002118:Calcium