title: Modeling of glucose-induced cAMP oscillations in pancreatic β cells: cAMP rocks when metabolism rolls.
abstract: Recent advances in imaging technology have revealed oscillations of cyclic adenosine monophosphate (cAMP) in insulin-secreting cells. These oscillations may be in phase with cytosolic calcium oscillations or out of phase. cAMP oscillations have previously been modeled as driven by oscillations in calcium, based on the known dependence of the enzymes that generate cAMP (adenylyl cyclase) and degrade it (phosphodiesterase). However, cAMP oscillations have also been reported to occur in the absence of calcium oscillations. Motivated by similarities between the properties of cAMP and metabolic oscillations in pancreatic β cells, we propose here that in addition to direct control by calcium, cAMP is controlled by metabolism. Specifically, we hypothesize that AMP inhibits adenylyl cyclase. We incorporate this hypothesis into the dual oscillator model for β cells, in which metabolic (glycolytic) oscillations cooperate with modulation of ion channels and metabolism by calcium. We show that the combination of oscillations in AMP and calcium in the dual oscillator model can account for the diverse oscillatory patterns that have been observed, as well as for experimental perturbations of those patterns. Predictions to further test the model are provided.
authors.affiliation: Department of Mathematics and Statistics, University of Maryland, Baltimore County, Baltimore, Maryland.
authors.forename: Bradford E
authors.initials: BE
authors.lastname: Peercy
authors.affiliation: Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland. Electronic address: asherman@nih.gov.
authors.forename: Arthur S
authors.initials: AS
authors.lastname: Sherman
authors.affiliation: Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, Florida.
authors.forename: Richard
authors.initials: R
authors.lastname: Bertram
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002413:Cations, Divalent / Q000378:metabolism; D003198:Computer Simulation; D000242:Cyclic AMP / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008564:Membrane Potentials / Q000502:physiology; D008954:Models, Biological; D010507:Periodicity; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism
chemical_list: D002413:Cations, Divalent; D000242:Cyclic AMP; D010727:Phosphoric Diester Hydrolases; D000262:Adenylyl Cyclases; D005947:Glucose; D002118:Calcium