Bertram, Previte, Sherman, Kinard, Satin, 2000

Model Status

This model has been rebuilt according to the author's original XPPAUT code, which can be found here. This version of the CellML model represents the fast bursting model where gs1=20. The model replicates figure 2 in the published paper. The model runs in both PCEnv and COR and the units are consistent.

Model Structure

Pancreatic beta-cells have been the subject of both experimental and theoretical studies for several decades. One reason for this interest has been the essential role beta-cells play in glucose homeostasis - they are the only source of insulin that most cells require in order to take up and metabolise glucose, and impairment of beta-cell function contributes to diabetes. A major focus of theoretical work has been beta-cell dynamics, especially in the form of bursting electrical activity. The bursts consist of active phases of Ca²⁺ -carrying action potentials alternating with silent phases of repolarisation and are accompanied by oscillations in cytosolic Ca²⁺ , which drive pulses of insulin secretion.

Experimentally, electrical activity in beta-cells is studied in two distinct preparations: islets of Langerhans, which are microorgans containing thousands of endocrine cells, and isolated cells. Pancreatic beta-cells exhibit bursting oscillations with a wide range of periods. Whereas periods in isolated cells are generally either a few seconds or a few minutes, in intact islets of Langerhans they are intermediate (10-60 seconds). In their 2000 publication, Richard Bertram, Joseph Previte, Arthur Sherman, Tracie A. Kinard and Leslie S. Satin develop a mathematical model for beta-cell electrical activity capable of generating this wide range of bursting oscillations. Unlike previously published models, bursting is driven by the interaction of two slow processes (I_s1 and I_s2 in the figure below), one with a relatively small time constant (1-5 seconds) and the other with a much larger time constant (1-2 minutes). Bursting on the intermediate time scale is generated without the need for a slow process having an intermediate time constant, hence phantom bursting. This mathematical model has been translated into a CellML description which can be downloaded in various formats as described in .

The complete original paper reference is cited below:

The Phantom Burster Model for Pancreatic beta-Cells, Richard Bertram, Joseph Previte, Arthur Sherman, Tracie A. Kinard and Leslie S. Satin, 2000, Biophysical Journal, 79, 2880-2892. PubMed ID: 11106596

Schematic diagram of the pancreatic beta-cell plasma membrane showing the ionic currents captured by the phantom burster model.