Model Reference Description: Model (ICa_voltage_clamp_25mV_model)

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Voltage clamp of total calcium current with -25mV plateau.
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-11
Publisher: Division of Bioengineering, National University of Singapore
Pubmed reference: 17486452
Comment [created by David Nickerson]:
A voltage clamp experiment examining the behaviour of the total membrane calcium current, as described in Corrias & Buist (2007). Importing generic clamp experiment and setting parameters for -25mV plateau potential.
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parameters
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-11
Publisher: Division of Bioengineering, National University of Singapore
Comment:
Here we define the specific parameters for the applied voltage clamp with -25mV plateau.
clamp_potential
Initial value: -25.0
Units: mV
clamp_start
Initial value: 1.214e3
Units: ms
clamp_end
Initial value: 9.0e3
Units: ms
Cai
Initial value: 3.5e-4
Units: mM
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interface
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-10
Publisher: Division of Bioengineering, National University of Singapore
Comment:
This component encapsulates the voltage clamp experiment and is designed to be imported and have the protocol specific variables defined.
Imported as: model
Untitled metadata
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-11
Publisher: Division of Bioengineering, National University of Singapore
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ICaL
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-04
Publisher: Division of Bioengineering, National University of Singapore
Comment:
Here we calculate the L-type calcium current. We expect the time, membrane potential, [Ca]i, and conductance to be set externally, and we provide access to the gating variables and the calculated current. This component encapsulates all others in this model and thus acts as an interface to the gating variable components, both local and imported.
Imported as: total_Ca_current
Untitled metadata
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-10
Publisher: Division of Bioengineering, National University of Singapore
ICaL=g_CaL⁢d⁢f⁢fCa⁢(Vm−ECa)
ICaL
Units: pA
g_CaL
Defined as: g_CaL
Units: nS
d
Defined as: gate
Units: dimensionless
f
Defined as: gate
Units: dimensionless
fCa
Defined as: fCa
Units: dimensionless
Vm
Defined as: Vm
Units: mV
ECa
Defined as: reversal_potential
Units: mV
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clamp_protocol
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-06
Publisher: Division of Bioengineering, National University of Singapore
Pubmed reference: 1852104
Comment:
Here we define the voltage clamp protocol used in Corrias & Buist (2007) to validate the total membrane calcium current. The voltage clamp is based on experimental recordings from Vogalis et al. (1991).
Imported as: clamp_protocol
Untitled metadata
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-10
Publisher: Division of Bioengineering, National University of Singapore
Vm={[-60mV]−time⁢([50.0mV]/[0.15e3ms])  if  (time≤[1.15e3ms])∧(time>[1.0e3ms])[-10.0mV]−(time−[1.15e3ms])⁢([-10.0mV]−clamp_potential/clamp_start−[1.15e3ms])  if  (time≤clamp_start)∧(time>[1.15e3ms])clamp_potential  if  (time≤clamp_end)∧(time>clamp_start)clamp_potential−(time−clamp_end)⁢(clamp_potential−−[60.0mV]/[9.5e3ms]−clamp_end)  if  (time≤[9.5e3ms])∧(time>clamp_end)[-60.0mV]  otherwise  
Vm
Units: mV
time
Defined as: time
Units: ms
clamp_potential
Defined as: clamp_potential
Units: mV
clamp_start
Defined as: clamp_start
Units: ms
clamp_end
Defined as: clamp_end
Units: ms
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Default model parameter values
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-05
Publisher: Division of Bioengineering, National University of Singapore
Comment:
Here we define the complete set of default parameter values.
Modification [modified by David Nickerson]:
Adding parameter data for the IKA current.
Modified: 2007-11-26
Modification [modified by David Nickerson]:
Separating out the calculation of the Ca temperature correction factor.
Modified: 2007-11-26
Imported as: default_parameters
Untitled metadata
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-10
Publisher: Division of Bioengineering, National University of Singapore
Tcorrection_Ca=Q10Ca(T−T_Ca/[10.0K])
Tcorrection_K=Q10K(T−T_K/[10.0K])
tau_d=tau_d_base⁢Tcorrection_Ca
tau_f=tau_f_base⁢Tcorrection_Ca
tau_xA2=tau_xA2_base⁢Tcorrection_K
Tcorrection_Ca
Units: dimensionless
Q10 temperature correction factor for calcium.
Q10Ca
Initial value: 2.1
Units: dimensionless
Metadata
Pubmed reference: 10099682
Comment:
Q10 value used to adjust the L-type calcium voltage dependent gating time constants to current temperature.
T
Initial value: 310.0
Units: K
Metadata
Comment:
The current temperature at which the model is defined.
T_Ca
Initial value: 297
Units: K
Metadata
Pubmed reference: 1703570
Comment:
The temperature at which the L-type calcium voltage dependent gating time constants were measured.
Tcorrection_K
Units: dimensionless
Q10 temperature correction factor for potassium.
Q10K
Initial value: 1.5
Units: dimensionless
Q10 value used to adjust the potassium voltage dependent gating time constants to current temperature.
Pubmed reference: 10394625
T_K
Initial value: 297
Units: K
tau_d
Units: ms
Metadata
Comment:
Actual time constant of activation gate of the L-type calcium current, adjusted to current temperature.
tau_d_base
Initial value: 0.47
Units: ms
Metadata
Comment:
The base time constant for the activation gate of the L-type calcium current, measured at a room temperature of 297 K.
tau_f
Units: ms
Metadata
Comment:
Actual time constant of inactivation gate of the L-type calcium current, adjusted to current temperature.
tau_f_base
Initial value: 86.0
Units: ms
Metadata
Pubmed reference: 1703570
Biological Entity: pyloric myocyte
Species: canine
Comment:
The base time constant for the inactivation gate of the L-type calcium current, measured at a room temperature of 297 K.
tau_xA2
Units: ms
Metadata
Comment:
Actual time constant of inactivation gate of the A-type potassium current, adjusted to current temperature.
tau_xA2_base
Initial value: 90.0
Units: ms
Metadata
Pubmed reference: 12381815
Biological Entity: gastric smooth muscle cell
Species: mouse
Comment:
The base time constant for the inactivation gate of the A-type potassium current, measured at a room temperature of 297 K.
Cai_rest
Initial value: 1.0e-4
Units: mM
Metadata
Comment:
The resting level of intracellular calcium. In the original C code this was evaluated as the value of [Ca]i some time interval before the first stimulus - perhaps should also implement that in this version of the model?
Cao
Initial value: 2.5
Units: mM
Extracellular calcium ion concentration.
Biological Entity: taenia coli
Species: guinea pig
Ko
Initial value: 5.9
Units: mM
Extracellular potassium ion concentration.
Biological Entity: taenia coli
Species: guinea pig
Ki
Initial value: 164.0
Units: mM
Intracellular potassium ion concentration.
Biological Entity: taenia coli
Species: guinea pig
g_CaL
Initial value: 65.0
Units: nS
Metadata
Pubmed reference: 1312782
Biological Entity: gastric smooth muscle
Species: canine
Comment:
Maximal conductance of the L-type calcium current.
d_V_half
Initial value: 17.0
Units: mV
Metadata
Pubmed reference: 7683715
Biological Entity: oesophageal muscularis mucosae
Species: New Zealand White rabbit
Comment:
Half maximal potential for voltage-dependent activation gate for L-type calcium current.
d_k
Initial value: 4.3
Units: mV
Metadata
Comment:
Slope factor for voltage dependence of L-type calcium current activation gate.
f_V_half
Initial value: 43.0
Units: mV
Metadata
Comment:
Half maximal potential for voltage-dependent inactivation gate for L-type calcium current.
f_k
Initial value: 8.9
Units: mV
Metadata
Comment:
Slope factor for voltage dependence of L-type calcium current inactivation gate.
hCa
Initial value: 201.4e-6
Units: mM
Metadata
Pubmed reference: 1312782
Biological Entity: gastric smooth muscle
Species: canine
Comment:
Calcium concentration for half maximal activation of the calcium dependent L-type calcium current inactivation gate.
sCa
Initial value: 13.1e-6
Units: mM
Metadata
Pubmed reference: 1312782
Biological Entity: gastric smooth muscle
Species: canine
Comment:
Slope factor for the calcium dependence of the calcium dependent L-type calcium current inactivation gate.
tau_fCa
Initial value: 2.0
Units: ms
Metadata
Pubmed reference: 14656705
Biological Entity: cardiac myocyte
Species: Homo sapiens
Comment:
Time constant for the calcium dependent L-type calcium current inactivation gate.
g_KA
Initial value: 9.0
Units: nS
Maximal conductance of A-type potassium channel.
Pubmed reference: 1383498
Biological Entity: gastric myocyte
Species: guinea pig
xA1_V_half
Initial value: 26.5
Units: mV
Half maximal potential for voltage-dependent activation gate for A-type potasium current.
Pubmed reference: 12381815
Biological Entity: gastric smooth muscle cell
Species: mouse
xA1_k
Initial value: 7.9
Units: mV
Slope factor for voltage dependence of A-type calcium current activation gate.
Pubmed reference: 12381815
Biological Entity: gastric smooth muscle cell
Species: mouse
xA2_V_half
Initial value: 65.0
Units: mV
Half maximal potential for voltage-dependent inactivation gate for A-type potasium current.
Pubmed reference: 12381815
Biological Entity: gastric smooth muscle cell
Species: mouse
xA2_k
Initial value: 6.2
Units: mV
Slope factor for voltage dependence of A-type calcium current inactivation gate.
Pubmed reference: 12381815
Biological Entity: gastric smooth muscle cell
Species: mouse
<source/>
Default model initial values
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-05
Publisher: Division of Bioengineering, National University of Singapore
Comment:
Here we define the complete set set of default initial conditions for the model's differental variables.
Modification [modified by David Nickerson]:
Adding A-type potassium current gating variable initial conditions.
Modified: 2007-11-27
Imported as: default_initial_conditions
Untitled metadata
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-10
Publisher: Division of Bioengineering, National University of Singapore
d_initial
Initial value: 4.54e-5
Units: dimensionless
f_initial
Initial value: 0.871
Units: dimensionless
fCa_initial
Initial value: 1.0
Units: dimensionless
xA1_initial
Initial value: 0.0
Units: dimensionless
xA2_initial
Initial value: 1.0
Units: dimensionless
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one_ion
Creator: David Nickerson (d.nickerson@auckland.ac.nz) Bioengineering Institute, The University of Auckland
Created: 2004-12-27
Publisher: Bioengineering Institute, The University of Auckland
Comment:
Calculate the Nernst reversal potential for one ionic specie. We expect the temperature, valence and ionic concentrations to be defined by the model importing this component. We make the gas and Faraday's constants available for others to use.
Imported as: ECa
Untitled metadata
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-10
Publisher: Division of Bioengineering, National University of Singapore
reversal_potential=(R⁢T/z⁢F)⁢ln(extracellular_concentration/intracellular_concentration)
reversal_potential
Units: mV
R
Initial value: 8314.472
Units: gas_constant
T
Defined as: T
Units: K
z
Defined as: two
Units: dimensionless
F
Initial value: 96485.0
Units: faradays_constant
extracellular_concentration
Defined as: Cao
Units: mM
intracellular_concentration
Defined as: Cai
Units: mM
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time
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-10
Publisher: Division of Bioengineering, National University of Singapore
Comment:
The actual definition of the time variable.
time
Initial value: 0.0
Units: ms
Metadata
Comment:
The actual definition of the time variable.
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parameters
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-10
Publisher: Division of Bioengineering, National University of Singapore
Comment:
The model parameters - in this case we use all default values and set [Ca]i to resting value directly from the default parameters. Here we just define the parameters needed for the calculation of ECa.
two
Initial value: 2.0
Units: dimensionless
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Standard Hodgkin-Huxley activation gate kinetics
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-04
Publisher: Division of Bioengineering, National University of Singapore
Comment:
The standard definition of a HH type activation gate. This component should be imported and all parameters defined.
Imported as: d_gate
Untitled metadata
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-04
Publisher: Division of Bioengineering, National University of Singapore
Comment:
Import the standard HH type activation gate for use as the L-type Ca current voltage dependent activation gate (d).
dgatedtime=gate_inf−gate/gate_tau
gate_inf=[1.0dimensionless]/[1.0dimensionless]+e−(V_half+Vm/k)
gate
Initial value: gate_initial
Units: dimensionless
Metadata
Comment:
This is the actual gating variable representing a standard HH type activation gate.
time
Defined as: time
Units: ms
Metadata
Comment:
The time variable needs to be defined for the activation gate component.
gate_inf
Units: dimensionless
Metadata
Comment:
The steady state activation gate value.
gate_tau
Defined as: tau_d
Units: ms
Metadata
Comment:
The activation gate time constant.
V_half
Defined as: d_V_half
Units: mV
Metadata
Comment:
The membrane potential at which the activation gate is half maximally activated.
Vm
Defined as: Vm
Units: mV
Metadata
Comment:
The membrane potential variable needs to be defined for the activation gate component.
k
Defined as: d_k
Units: mV
Metadata
Comment:
The slope factor for the voltage dependence of the activation gate.
gate_initial
Defined as: d_initial
Units: dimensionless
Metadata
Comment:
The initial value for the activation gate needs to be defined.
<source/>
Standard Hodgkin-Huxley inactivation gate kinetics
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-04
Publisher: Division of Bioengineering, National University of Singapore
Comment:
The standard definition of a HH type inactivation gate. This component should be imported and all parameters defined.
Imported as: f_gate
Untitled metadata
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-04
Publisher: Division of Bioengineering, National University of Singapore
Comment:
Import the standard HH type inactivation gate for use as the L-type Ca current voltage dependent inactivation gate (f).
dgatedtime=gate_inf−gate/gate_tau
gate_inf=[1.0dimensionless]/[1.0dimensionless]+eV_half+Vm/k
gate
Initial value: gate_initial
Units: dimensionless
Metadata
Comment:
This is the actual gating variable representing a standard HH type inactivation gate.
time
Defined as: time
Units: ms
Metadata
Comment:
The time variable needs to be defined for the inactivation gate component.
gate_inf
Units: dimensionless
Metadata
Comment:
The steady state inactivation gate value.
gate_tau
Defined as: tau_f
Units: ms
Metadata
Comment:
The activation gate time constant.
V_half
Defined as: f_V_half
Units: mV
Metadata
Comment:
The membrane potential at which the inactivation gate is half maximally inactivated.
Vm
Defined as: Vm
Units: mV
Metadata
Comment:
The membrane potential variable needs to be defined for the inactivation gate component.
k
Defined as: f_k
Units: mV
Metadata
Comment:
The slope factor for the voltage dependence of the inactivation gate.
gate_initial
Defined as: f_initial
Units: dimensionless
Metadata
Comment:
The initial value for the inactivation gate needs to be defined.
<source/>
fCa_gate
Creator: David Nickerson (david.nickerson@nus.edu.sg) Division of Bioengineering, National University of Singapore
Created: 2007-09-04
Publisher: Division of Bioengineering, National University of Singapore
Comment:
This is the intracellular calcium dependent inactivation gate for the L-type calcium current.
dfCadtime=fCa_inf−fCa/tau_fCa
fCa_inf=[1.0dimensionless]−[1.0dimensionless]/[1.0dimensionless]+e−(Cai−Cai_rest−hCa/sCa)
fCa
Initial value: fCa_initial
Units: dimensionless
time
Defined as: time
Units: ms
fCa_inf
Units: dimensionless
tau_fCa
Defined as: tau_fCa
Units: ms
Cai
Defined as: Cai
Units: mM
Cai_rest
Defined as: Cai_rest
Units: mM
hCa
Defined as: hCa
Units: mM
sCa
Defined as: sCa
Units: mM
fCa_initial
Defined as: fCa_initial
Units: dimensionless

Units definitions

mV
(1000⁢kilogram) ⁢(metre2) ⁢(second-3) ⁢(ampere-1)
ms
1000⁢second
mM
(1e+09⁢mole) ⁢(1e-09⁢metre-3)
pA
1e+12⁢ampere
nS
(1e+09⁢kilogram-1) ⁢(metre-2) ⁢(second3) ⁢(ampere2)
dimensionless
dimensionless
K
kelvin
gas_constant
(1e+12⁢kilogram) ⁢(1e-09⁢mole-1) ⁢(metre2) ⁢(kelvin-1) ⁢(second-2)
faradays_constant
(1e-09⁢mole-1) ⁢(1e+09⁢second) ⁢(ampere)
Created: 05:35:38 2008-02-05 (UTC) by CellMLSimulator