Effects of extracellular calcium on electrical bursting and intracellular and luminal calcium oscillations in insulin secreting pancreatic beta-cells.
The extracellular calcium concentration has interesting effects on bursting of pancreatic beta-cells. The mechanism underlying the extracellular Ca2+ effect is not well understood. By incorporating a low-threshold transient inward current to the store-operated bursting model of Chay, this paper elucidates the role of the extracellular Ca2+ concentration in influencing electrical activity, intracellular Ca2+ concentration, and the luminal Ca2+ concentration in the intracellular Ca2+ store. The possibility that this inward current is a carbachol-sensitive and TTX-insensitive Na+ current discovered by others is discussed. In addition, this paper explains how these three variables respond when various pharmacological agents are applied to the store-operated model.
Chay
T R
TR
Department of Biological Sciences, University of Pittsburgh, Pennsylvania 15260, USA. trc1@vms.cis.pitt.edu
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology*; D015220:Calcium Channels / Q000502:physiology; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology; D005089:Exocytosis; D019204:GTP-Binding Proteins / Q000502:physiology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007473:Ion Channels / Q000502:physiology*; D007515:Islets of Langerhans / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D008433:Mathematics; D008954:Models, Biological; D009991:Oscillometry; D015221:Potassium Channels / Q000502:physiology; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology
D015220:Calcium Channels; D007328:Insulin; D007473:Ion Channels; D015221:Potassium Channels; D015222:Sodium Channels; D013779:Tetrodotoxin; D002217:Carbachol; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D000252:Calcium-Transporting ATPases; D002118:Calcium