The Phantom Burster Model For Pancreatic Beta-Cells
James
Lawson
Bioengineering Institute, University of Auckland
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 slow bursting model where gs1=3. The model replicates figure 4 in the published paper (please note you need to run the model for at least 300 seconds to get past the initial unstable stage). 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 (Is1
and Is2
in
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
cell schematic for the model
Schematic diagram of the pancreatic beta-cell plasma membrane showing the ionic currents captured by the phantom burster model.
Joseph
Previte
James
Lawson
Richard
Added more metadata.
Autumn
Cuellar
A
James
Lawson
Richard
2002-07-18
2009-05-15T16:10:00+12:00
Fixed errors detected by ValidateCellML, including connection duplication and namespace mixing.
The Bertram et al 2000 phantom burster model for pancreatic beta-cells.
pancreatic beta-cell
keyword
calcium dynamics
electrophysiology
beta cell
pancreas
1000
2000-12
Tracie
Kinard
A
The University of Auckland, Bioengineering Institute
11106596
James Lawson
This is the CellML description of Bertram et al's 2000 phantom burster model for pancreatic beta-cells.
100
10000
0.001
2003-04-09
Arthur
Sherman
Biophysical Journal
The University of Auckland
The Bioengineering Institute
j.lawson@auckland.ac.nz
Richard
Bertram
Catherine Lloyd
Added publication date information.
5000
100000
0.001
bdf15
2007-08-08T00:00:00+00:00
This model has been rebuilt according to the author's original XPPAUT code, which can be found at http://www.math.fsu.edu/~bertram/software/islet/BJ_04a.ode . Unfortunately the model is still unable to produce the correct output. This file is known to run in PCEnv.
Catherine
Lloyd
May
The Phantom Burster Model for Pancreatic Beta Cells
79
2880
2892
Leslie
Satin
S