Abstract:
:We investigate the hypothesis that two classes of Ca2+ currents, one quickly inactivated by Ca2+ and one slowly inactivated by voltage, contribute to bursting electrical activity in pancreatic islets. A mathematical model of these currents is fit to the experimental whole-cell current-voltage and inactivation profiles, thereby fixing the Ca2+ conductance and all activation and inactivation parameters. Incorporating these currents into a model that includes delayed rectifier K+ channels and ATP-sensitive K+ channels, we show that only abnormal bursting is obtained. Modification of activation parameters to increase Ca2+ channel open times, as suggested by experiment, yields a more robust bursting similar to that observed in intact islets. This reinforces the suggestion that in addition to ATP-sensitive K+ channels, Ca2+ channels may serve as glucose sensors in the beta cell.
journal_name
Proc Natl Acad Sci U S Aauthors
Keizer J,Smolen Pdoi
10.1073/pnas.88.9.3897subject
Has Abstractpub_date
1991-05-01 00:00:00pages
3897-901issue
9eissn
0027-8424issn
1091-6490journal_volume
88pub_type
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