Slow wave propagation in the guinea-pig gastric antrum (Hirst et al. 2006, Edwards and Hirst 2006)

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Accession:87581
"(Edwards and Hirst 2006) provides an electrical description of the propagation of slow waves and pacemaker potentials in the guinea-pig gastric antrum in anal and circumferential directions. As electrical conduction between laterally adjacent circular muscle bundles is regularly interrupted, anal conduction of pacemaker potentials was assumed to occur via an electrically interconnected chain of myenteric interstitial cells of Cajal (ICCMY). ICCMY were also connected resistively to serially connected compartments of longitudinal muscle. Circumferential conduction occurred in a circular smooth muscle bundle that was represented as a chain of electrically connected isopotential compartments: each compartment contained a proportion of intramuscular interstitial cells of Cajal (ICCIM) that are responsible for the regenerative component of the slow wave. The circular muscle layer, which contains ICCIM, and the ICCMY network incorporated a mechanism, modelled as a two-stage chemical reaction, which produces an intracellular messenger. ... The model generates pacemaker potentials and slow waves with propagation velocities similar to those determined in the physiological experiments described in the accompanying paper."
Reference:
1 . Edwards FR, Hirst GD (2006) An electrical analysis of slow wave propagation in the guinea-pig gastric antrum. J Physiol 571:179-89 [PubMed]
2 . Hirst GD, Garcia-Londono AP, Edwards FR (2006) Propagation of slow waves in the guinea-pig gastric antrum. J Physiol 571:165-77 [PubMed]
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Model Information (Click on a link to find other models with that property)
Model Type: Realistic Network;
Brain Region(s)/Organism: Enteric nervous system;
Cell Type(s): Myenteric interstitial cell of Cajal (ICCMY); Intramuscular interstitial cell of Cajal (ICCIM);
Channel(s):
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: MATLAB;
Model Concept(s): Temporal Pattern Generation; Oscillations; Spatio-temporal Activity Patterns;
Implementer(s): Edwards, Frank [frank.edwards at anu.edu.au];
/
slowwave
readme.txt
FCs134.dat
Figure4.m
Figure6.m
ICs180.dat
                            
This is the readme for the models associated with the paper

     Edwards FR, Hirst GD (2006) An electrical analysis of slow wave
     propagation in the guinea-pig gastric antrum. 
     J Physiol 571:179-89

which is the companion paper to another which describes the
physiologically acquired data:

     Hirst GD, Garcia-Londono AP, Edwards FR (2006) Propagation of
     slow waves in the guinea-pig gastric antrum.
     J Physiol 571:165-77

Usage:

These Matlab files generate parts of figure 4 - a
longitudinal string of 20 ICC compartments with attached longitudinal
muscle compartments.

This file is called Figure4.m and requires ICs180.dat.  If
you run it as it is, it will produce figure 4A as Matlab figure 50
(green line) after about 10 seconds on my Dell laptop (3/29/07).

If you modify line 26 to read PASSIVE=0, then it will produce a
version of figure 4C as Matlab figure 51 after about 37 minutes.

If you subsequently modify line 45 to read UNITS=0, and rerun it then
it will produce a smooth looking version of figure 4C after about 1
minute.  This option uses simple analytic functions to approximate
conductance modulations, rather than random number generated
stochastic discharges of unitary conductance modulations.  It runs a
lot faster and was useful for shaping things up.  Also useful for
quick verification.

Also attached is Figure6.m which requires FCs134.dat.  This models a
circumferential string of 16 compartments of antral circular muscle,
with the first 6 connected to ICC compartments each with an attached
longitudinal muscle compartment.  Driving the first ICC compartment is
a corporal circular muscle compartment.

Run as it is, it will produce figure 6A as Matlab figure 20 (green
line) after about 15 seconds.

If you modify line 31 to read PASSIVE=0, then it will produce a
version of figure 6C as Matlab figure 21 after about 37 minutes.

If you subsequently modify line 51 to read UNITS=0, and rerun it then
it will produce a smooth looking version of figure 6C after about 45
seconds.

The only flagrant contradiction I have noticed in the paper is on line
13 of p184.  The value in brackets should read 10 mV, not 1 mV.  This
value appears as NUDGE in both Matlab files.

I apologize in advance for the lack of elegance of the runnable files.
They are replete with unused options and commented out tracts to draw
intermediate graphs and stuff.  Many parameters are dependent or
various multiplications, and so appear cryptic.... my target was
development speed rather than Matlab's programming advantages.

PlatCond and CMBCond are the most interesting (more or less identical)
subroutines.  They define the time locations of stochastic unitary
conductance modulations whose mean frequency varies with membrane
potential.

Dr Frank Edwards
3/29/07