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An electrical description of the generation of slow waves in the antrum of the guinea‐pig
Author(s) -
Edwards F. R.,
Hirst G. D. S.
Publication year - 2005
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2004.077123
Subject(s) - interstitial cell of cajal , antrum , anatomy , sucrose gap , chemistry , compartment (ship) , enteric nervous system , circular muscle , membrane potential , biophysics , biology , neuroscience , smooth muscle , stomach , endocrinology , biochemistry , oceanography , geology
This paper provides an electrical description of the generation of slow waves in the guinea‐pig gastric antrum. A short segment of a circular smooth muscle bundle with an attached network of myenteric interstitial cells of Cajal (ICC‐MY) and longitudinal muscle sheet was modelled as three electrical compartments with resistive connexions between the ICC‐MY compartment and each of the smooth muscle compartments. The circular smooth muscle layer contains a proportion of intramuscular interstitial cells of Cajal (ICC‐IM), responsible for the regenerative component of the slow wave. Hence the equivalent cell representing the circular muscle layer incorporated a mechanism, modelled as a two stage reaction, which produces an intracellular messenger. The first stage of the reaction is proposed to be activated in a voltage‐dependent manner as described by Hodgkin and Huxley. A similar mechanism was incorporated into the equivalent cell describing the ICC‐MY network. Spontaneous discrete transient depolarizations, termed unitary potentials, are detected in records taken from either bundles of circular smooth muscle containing ICC‐IM or from ICC‐MY. In the simulation the mean rate of discharge of unitary potentials was allowed to vary with the concentration of messenger according to a conventional dose–effect relationship. Such a mechanism, which describes regenerative potentials generated by the circular muscle layer, also simulated the plateau component of the pacemaker potential in the ICC‐MY network. A voltage‐sensitive membrane conductance was included in the ICC‐MY compartment; this was used to describe the primary component of the pacemaker potential. The model generates a range of membrane potential changes with properties similar to those generated by the three cell types present in the intact tissue.