Dataset Information

Morris1981_MuscleFibre_Voltage_reduced

ABSTRACT: This is the reduced model of the voltage oscillations in barnacle muscle fibers, generally known as the Morris-Lecar model (eg. wikipedia), described in the article: Voltage oscillations in the barnacle giant muscle fiber. Morris C, Lecar H. Biophys J. 1981 Jul;35(1):193-213. PubmedID:7260316; DOI:10.1016/S0006-3495(81)84782-0 Abstract: Barnacle muscle fibers subjected to constant current stimulation produce a variety of types of oscillatory behavior when the internal medium contains the Ca++ chelator EGTA. Oscillations are abolished if Ca++ is removed from the external medium, or if the K+ conductance is blocked. Available voltage-clamp data indicate that the cell's active conductance systems are exceptionally simple. Given the complexity of barnacle fiber voltage behavior, this seems paradoxical. This paper presents an analysis of the possible modes of behavior available to a system of two noninactivating conductance mechanisms, and indicates a good correspondence to the types of behavior exhibited by barnacle fiber. The differential equations of a simple equivalent circuit for the fiber are dealt with by means of some of the mathematical techniques of nonlinear mechanics. General features of the system are (a) a propensity to produce damped or sustained oscillations over a rather broad parameter range, and (b) considerable latitude in the shape of the oscillatory potentials. It is concluded that for cells subject to changeable parameters (either from cell to cell or with time during cellular activity), a system dominated by two noninactivating conductances can exhibit varied oscillatory and bistable behavior. The model consists of the differential equations (9) and (2) given on pages 205 and 196 of the article. There seems to be a typo in the figure caption of figure 9. Using V2 = 15 instead of -15 allows to reproduce the results. Originally created by libAntimony v1.4 (using libSBML 3.4.1)

SUBMITTER: Lukas Endler

PROVIDER: BIOMD0000000280 | BioModels | 2010-11-24

REPOSITORIES: BioModels

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Publications

Voltage oscillations in the barnacle giant muscle fiber.

Morris C C Lecar H H

Biophysical journal 19810701 1

Barnacle muscle fibers subjected to constant current stimulation produce a variety of types of oscillatory behavior when the internal medium contains the Ca++ chelator EGTA. Oscillations are abolished if Ca++ is removed from the external medium, or if the K+ conductance is blocked. Available voltage-clamp data indicate that the cell's active conductance systems are exceptionally simple. Given the complexity of barnacle fiber voltage behavior, this seems paradoxical. This paper presents an analys ...[more]

PMID: 7260316

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Project description:This is the full model (eq. 1 and 2) of the voltage oscillations in barnacle muscle fibers described in the article: Voltage oscillations in the barnacle giant muscle fiber. Morris C, Lecar H. Biophys J. 1981 Jul;35(1):193-213. PubmedID:7260316; DOI:10.1016/S0006-3495(81)84782-0 Abstract: Barnacle muscle fibers subjected to constant current stimulation produce a variety of types of oscillatory behavior when the internal medium contains the Ca++ chelator EGTA. Oscillations are abolished if Ca++ is removed from the external medium, or if the K+ conductance is blocked. Available voltage-clamp data indicate that the cell's active conductance systems are exceptionally simple. Given the complexity of barnacle fiber voltage behavior, this seems paradoxical. This paper presents an analysis of the possible modes of behavior available to a system of two noninactivating conductance mechanisms, and indicates a good correspondence to the types of behavior exhibited by barnacle fiber. The differential equations of a simple equivalent circuit for the fiber are dealt with by means of some of the mathematical techniques of nonlinear mechanics. General features of the system are (a) a propensity to produce damped or sustained oscillations over a rather broad parameter range, and (b) considerable latitude in the shape of the oscillatory potentials. It is concluded that for cells subject to changeable parameters (either from cell to cell or with time during cellular activity), a system dominated by two noninactivating conductances can exhibit varied oscillatory and bistable behavior. The model consists of the differential equations (1) and (2) given on pages 195 and 196 of the article. There is one typo in the equation for I in (1), gL(VL) should be gL(V - VL). This was changed in the SBML file. As there are no current values given, for reproducing the time courses in figure 6 an applied current of 50 uA was assumed. The legend for the broken and the full line in this figure seems to be confounded in the article. Originally created by libAntimony v1.4 (using libSBML 3.4.1)

Dataset Information

Morris1981_MuscleFibre_Voltage_reduced

Publications

Voltage oscillations in the barnacle giant muscle fiber.

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