calcium dynamics
electrophysiology
The JWR model creates a new mathematical model to describe the
L-type calcium channel that is based on the experimentally observed
mode-switching behaviour of the channel. Inactivation occurs as
calcium ion binding induces the channel to switch (from mode normal)
to a mode in which transitions to open states are extremely slow
(mode Ca). The channel has one voltage inactivation gate, y. As well
as Ca, the channel is assumed permeable to K ions also.
The JWR model creates a new mathematical model to describe the
L-type calcium channel that is based on the experimentally observed
mode-switching behaviour of the channel. Inactivation occurs as
calcium ion binding induces the channel to switch (from mode normal)
to a mode in which transitions to open states are extremely slow
(mode Ca). The channel has one voltage inactivation gate, y. As well
as Ca, the channel is assumed permeable to K ions also.
May
Lloyd
May
Catherine
Catherine
Lloyd
The voltage- and time-dependent activation gate for the
time-dependent potassium current - the X gate.
The voltage- and time-dependent activation gate for the
time-dependent potassium current - the X gate.
The Na/Ca exchanger component describes how a protein molecule in
the cell surface membrane transports Na ions into the cytosol and
exports Ca ions into the extracellular volume, in a ratio of 3:1
respectively.
The Na/Ca exchanger component describes how a protein molecule in
the cell surface membrane transports Na ions into the cytosol and
exports Ca ions into the extracellular volume, in a ratio of 3:1
respectively.
Biophysical Journal
Biophysical Journal
The University of Auckland
The Bioengineering Research Group
The Bioengineering Research Group
The University of Auckland
Mammalia
The Jafri-Rice-Winslow Model for Calcium Regulation in the Ventricular
Myocyte, 1997
Ventricular Myocyte
2001-10-19
2001-10-19
May
Lloyd
May
Lloyd
Catherine
Catherine
The voltage-dependent activation gate for the fast sodium current -
the m gate.
The voltage-dependent activation gate for the fast sodium current -
the m gate.
Removed document type definition as this is declared as optional
according to the W3C recommendation.
Removed document type definition as this is declared as optional
according to the W3C recommendation.
This model has been curated and the output checked against the original paper.
This model has been curated and the output checked against the original paper.
The kinetics of the y gate.
The kinetics of the y gate.
Lloyd
Catherine
Catherine
May
Lloyd
May
The calcium pump current.
The calcium pump current.
John
Rice
Rice
John
Jeremy
Jeremy
1149
1149
74
Cardiac Ca2+ Dynamics: The Roles of Ryanodine Receptor Adaptation and Sarcoplasmic Reticulum Load
1168
74
1168
Cardiac Ca2+ Dynamics: The Roles of Ryanodine Receptor Adaptation and Sarcoplasmic Reticulum Load
The opening rate of the h gate.
The opening rate of the h gate.
Calculation of the background calcium current.
Calculation of the background calcium current.
The total nonspecific calcium activated current.
The total nonspecific calcium activated current.
Calculate the translocation flux between the uptake (NSR) and
release (JSR) stores.
Calculate the translocation flux between the uptake (NSR) and
release (JSR) stores.
The rate of change of extracellular potassium ion concentration.
The rate of change of extracellular potassium ion concentration.
Calculate the calcium flux from the diffusion of calcium out of the
restricted subspace into the myoplasm.
Calculate the calcium flux from the diffusion of calcium out of the
restricted subspace into the myoplasm.
2007-05-24T11:52:30+12:00
2007-05-24T11:52:30+12:00
Corrected several equations, variable units and their initial values.
Corrected several equations, variable units and their initial values.
This model has been curated by Penny Noble of Oxford University and is known to run in PCEnv and COR. A PCEnv session is also associated with this file.
This model has been curated by Penny Noble of Oxford University and is known to run in PCEnv and COR. A PCEnv session is also associated with this file.
Lloyd
Catherine
Catherine
May
Lloyd
May
The time-dependent potassium current has an X^2 dependence on it's
activation gate, and an Xi inactivation gate. This channel is also
assumed permeable to sodium ions.
The time-dependent potassium current has an X^2 dependence on it's
activation gate, and an Xi inactivation gate. This channel is also
assumed permeable to sodium ions.
The voltage-dependent inactivation gate for the fast sodium current
- the h gate.
The voltage-dependent inactivation gate for the fast sodium current
- the h gate.
Altered some of the connections.
Altered some of the connections.
Calculation of the fast sodium current using the three
Hodkin-Huxley type voltage-dependent gating variables m, h, and j.
Calculation of the fast sodium current using the three
Hodkin-Huxley type voltage-dependent gating variables m, h, and j.
Lloyd
Catherine
Catherine
May
Lloyd
May
The sodium reversal potential.
The sodium reversal potential.
Corrected equations: alpha_j_calculation and beta_j_calculation in
fast_sodium_current_j_gate, alpha_X_calculation and beta_X_calculation in time_dependent_potassium_current_X_gate, and f_NaK_calculation and
i_NaK_calculation in Ca_release_current_from_JSR.
Corrected equations: alpha_j_calculation and beta_j_calculation in
fast_sodium_current_j_gate, alpha_X_calculation and beta_X_calculation in time_dependent_potassium_current_X_gate, and f_NaK_calculation and
i_NaK_calculation in Ca_release_current_from_JSR.
John
Jeremy
Jeremy
Rice
John
Rice
Saleet
Jafri
M
M
Saleet
Jafri
Cardiac Ca2+ Dynamics: The Roles of Ryanodine Receptor Adaptation and Sarcoplasmic Reticulum Load (Extended Model)
The University of Auckland, Bioengineering Research Group
Ventricular Myocyte
The Jafri-Rice-Winslow Model for Calcium Regulation in the Ventricular
Myocyte, 1997
Mammalia
Noble
Noble
Penny
Penny
J
J
Catherine
Catherine
Lloyd
May
Lloyd
May
The University of Auckland, Bioengineering Research Group
The channel's reversal potential.
The channel's reversal potential.
Calculate the current.
Calculate the current.
Calculation of the background sodium current.
Calculation of the background sodium current.
Corrected equations.
Corrected equations.
The potassium permeability of the channel, which depends on the
calcium current component.
The potassium permeability of the channel, which depends on the
calcium current component.
3000
0.2
0.1
100000
bdf15
3000
100000
The rate of change of intracellular potassium ion concentration.
The rate of change of intracellular potassium ion concentration.
Keep track of the concentration of calcium ions bound to high and
low affinity troponin binding sites.
Keep track of the concentration of calcium ions bound to high and
low affinity troponin binding sites.
Several variables have been given cmeta:id's to allow creation of a PCEnv session file.
Several variables have been given cmeta:id's to allow creation of a PCEnv session file.
In the JRW model, subcellular calcium regulatory mechanisms are
described in detail. There are six calcium fluxes to consider;
J_rel, J_leak, J_up, J_tr, J_xfer and J_trpn. In addition, three
membrane current fluxes are also necessary for the formulation of
calcium regulation; i_p_Ca, i_Ca_L_Ca and i_NaCa.
In the JRW model, subcellular calcium regulatory mechanisms are
described in detail. There are six calcium fluxes to consider;
J_rel, J_leak, J_up, J_tr, J_xfer and J_trpn. In addition, three
membrane current fluxes are also necessary for the formulation of
calcium regulation; i_p_Ca, i_Ca_L_Ca and i_NaCa.
The reversal potential of the channel.
The reversal potential of the channel.
2002-05-06
2002-05-06
Corrected several equations.
Corrected several equations.
ryanodine receptor
calcium dynamics
Lawson
Lawson
Richard
James
James
Richard
The activation variable.
The activation variable.
The voltage-dependent inactivation gate for the L-type calcium
channel - the y gate.
The voltage-dependent inactivation gate for the L-type calcium
channel - the y gate.
Raimond
Winslow
Raimond
L
L
Winslow
The steady-state approximation for the K1 gating kinetics.
The steady-state approximation for the K1 gating kinetics.
keyword
Calculation of the maximal channel conductance, dependent on
extracellular potassium concentration.
Calculation of the maximal channel conductance, dependent on
extracellular potassium concentration.
This is a dummy equation that we simply use to make grabbing the
value in CMISS much easier.
This is a dummy equation that we simply use to make grabbing the
value in CMISS much easier.
The time-independent potassium current.
The time-independent potassium current.
The opening rate of the X gate.
The opening rate of the X gate.
The maximal calcium current through the channel.
The maximal calcium current through the channel.
The kinetics of the j gate.
The kinetics of the j gate.
2002-02-25
2002-02-25
The maximal sodium component current.
The maximal sodium component current.
Ventricular Myocyte
ryanodine receptor
The voltage-dependent slow inactivation gate for the fast sodium
current - the j gate.
The voltage-dependent slow inactivation gate for the fast sodium
current - the j gate.
The closing rate of the j gate.
The closing rate of the j gate.
L
Winslow
Winslow
L
Raimond
Raimond
Calculate the leakage flux from the NSR into the myoplasm.
Calculate the leakage flux from the NSR into the myoplasm.
The kinetics of the state transitions in mode normal.
In the normal mode, the calcium channel is able to make the
transition to the open, conducting state (O) from the closed state
(C) at a normal rate.
The kinetics of the state transitions in mode normal.
In the normal mode, the calcium channel is able to make the
transition to the open, conducting state (O) from the closed state
(C) at a normal rate.
Catherine
Lloyd
May
Lloyd
May
Catherine
The reversal potential for the background calcium current.
The reversal potential for the background calcium current.
Calculation of the Na/K pump current.
Calculation of the Na/K pump current.
2001-09-24T00:00:00+00:00
2001-09-24T00:00:00+00:00
Xi is the inward rectification parameter and is given by the
following equation.
Xi is the inward rectification parameter and is given by the
following equation.
The sodium background current is a time-independent diffusion of
Na ions down their electrochemical gradient, through the cell
surface membrane into the cytosol.
The sodium background current is a time-independent diffusion of
Na ions down their electrochemical gradient, through the cell
surface membrane into the cytosol.
Calculation of the time-dependent potassium current.
Calculation of the time-dependent potassium current.
Calcium is buffered by calmodulin (CMDN) in the subspace and
myoplasm, and by calsequestrin (CSQN) in the JSR. These are fast
buffers and their effect is modelled using the rapid buffering
approximation.
Calcium is buffered by calmodulin (CMDN) in the subspace and
myoplasm, and by calsequestrin (CSQN) in the JSR. These are fast
buffers and their effect is modelled using the rapid buffering
approximation.
The main component of the model which defines the action potential.
The main component of the model which defines the action potential.
Calculation of the Na/Ca exchanger current.
Calculation of the Na/Ca exchanger current.
Rate constants for state changes in mode Ca (corresponding to
alpha-prime and beta-prime in the JRW paper).
Rate constants for state changes in mode Ca (corresponding to
alpha-prime and beta-prime in the JRW paper).
The calcium background current describes a time-independent
diffusion of Ca ions down their electrochemical gradient through the
cell surface membrane into the cytosol. However, calcium is not
allowed to accumulate to high intracellular concentrations. This
influx is balanced by the Ca ion extrusion through the Na-Ca
exchanger and the sarcolemmal Ca pump.
The calcium background current describes a time-independent
diffusion of Ca ions down their electrochemical gradient through the
cell surface membrane into the cytosol. However, calcium is not
allowed to accumulate to high intracellular concentrations. This
influx is balanced by the Ca ion extrusion through the Na-Ca
exchanger and the sarcolemmal Ca pump.
1998-03-01
1998-03-01
c.lloyd@auckland.ac.nz
c.lloyd@auckland.ac.nz
Catherine Lloyd
Catherine Lloyd
Lloyd
Lloyd
Catherine
May
Catherine
May
Rate constants for state changes in mode normal.
Rate constants for state changes in mode normal.
Calculate the uptake flux into the NSR from the myoplasm.
Calculate the uptake flux into the NSR from the myoplasm.
The "open" RyR's are those P_O1 and P_O2 states.
The "open" RyR's are those P_O1 and P_O2 states.
James Lawson
James Lawson
The reversal potential for the background sodium channel.
The reversal potential for the background sodium channel.
The maximal potassium component current.
The maximal potassium component current.
Saleet
Saleet
M
M
Jafri
Jafri
Added some initial values from Penny Noble's documentation.
Added some initial values from Penny Noble's documentation.
Catherine
May
May
Lloyd
Lloyd
Catherine
The plateau potassium current component contains the equations which
describe the contribution of a time independent [K]o-insensitive
channel at plateau potentials.
The plateau potassium current component contains the equations which
describe the contribution of a time independent [K]o-insensitive
channel at plateau potentials.
9512016
9512016
Changed tau_y_calculation after checking mathml using the validator.
Changed tau_y_calculation after checking mathml using the validator.
The closing rate of the h gate.
The closing rate of the h gate.
The following equation calculates the reversal potential of the
time-independent potassium current.
The following equation calculates the reversal potential of the
time-independent potassium current.
electrophysiology
Ventricular Myocyte
The potential offset for the channel.
The potential offset for the channel.
The descriptions of the rate of change of [Na]i and [K]i are the
same as the LR-II model.
The descriptions of the rate of change of [Na]i and [K]i are the
same as the LR-II model.
The time constants for the K1 gate are small enough that the gating
variable can be approximated with it's steady-state value.
The time constants for the K1 gate are small enough that the gating
variable can be approximated with it's steady-state value.
keyword
2001-12-07
2001-12-07
The calcium release flux from the JSR into the restricted subspace
is governed by the fraction of RyR channels in an open state.
The calcium release flux from the JSR into the restricted subspace
is governed by the fraction of RyR channels in an open state.
The reversal potential of the channel.
The reversal potential of the channel.
The time-independent inactivation gate for the time-dependent
potassium channel.
The time-independent inactivation gate for the time-dependent
potassium channel.
The sodium potassium pump is an active protein in the cell membrane
which couples the free energy released by the hydrolysis of ATP to
the movement of Na and K ions against their electrochemical
gradients through the cell membrane.
The sodium potassium pump is an active protein in the cell membrane
which couples the free energy released by the hydrolysis of ATP to
the movement of Na and K ions against their electrochemical
gradients through the cell membrane.
The rate of change of intracellular sodium ion concentration.
The rate of change of intracellular sodium ion concentration.
Calculation of the calcium current component of the total channel
current, given as the maximal current multiplied by the
voltage-dependent inactivation gate and the open probability of the
channel based on the mode-switching model.
Calculation of the calcium current component of the total channel
current, given as the maximal current multiplied by the
voltage-dependent inactivation gate and the open probability of the
channel based on the mode-switching model.
The potassium component of the channel's current.
The potassium component of the channel's current.
The opening rate of the j gate.
The opening rate of the j gate.
The kinetics of the X gate.
The kinetics of the X gate.
The kinetic equations governing the transitions between the four
states used to model the RyR's.
The kinetic equations governing the transitions between the four
states used to model the RyR's.
2007-06-22T12:55:26+12:00
2007-06-22T12:55:26+12:00
This is the CellML description of Jafri, Rice and Winslow's mathematical model for calcium regulation in the ventricular myocyte. It is based on an accurate model of the membrane currents and adds a more sophisticated model of calcium handling. The JRW model is based on the LR-II model for ventricular action potentials, with several modifications.
This is the CellML description of Jafri, Rice and Winslow's mathematical model for calcium regulation in the ventricular myocyte. It is based on an accurate model of the membrane currents and adds a more sophisticated model of calcium handling. The JRW model is based on the LR-II model for ventricular action potentials, with several modifications.
2002-01-04
2002-01-04
The closing rate of the K1 gate.
The closing rate of the K1 gate.
The kinetics of the state transitions in mode Ca.
Calcium binding to the Ca channel induces a conformational change
from normal mode to mode Ca. This effectively inhibits the
conduction of calcium ions because in mode Ca, the calcium channel
makes the transition to the open, conducting state (O) extremely
slowly.
The kinetics of the state transitions in mode Ca.
Calcium binding to the Ca channel induces a conformational change
from normal mode to mode Ca. This effectively inhibits the
conduction of calcium ions because in mode Ca, the calcium channel
makes the transition to the open, conducting state (O) extremely
slowly.
The closing rate of the X gate.
The closing rate of the X gate.
Calculation of the maximal channel conductance, dependent on
extracellular potassium concentration.
Calculation of the maximal channel conductance, dependent on
extracellular potassium concentration.
The sodium component of the channel's current.
The sodium component of the channel's current.
The fast sodium current component contains the differential
equations governing the influx of sodium ions through the cell
surface membrane into the cell.
The fast sodium current component contains the differential
equations governing the influx of sodium ions through the cell
surface membrane into the cell.
The nonspecific calcium activated current describes a channel which
is activated by calcium ions, but is permeable to only sodium and
potassium ions.
The nonspecific calcium activated current describes a channel which
is activated by calcium ions, but is permeable to only sodium and
potassium ions.
The kinetics of the h gate.
The kinetics of the h gate.
The kinetics of calcium binding to the myoplasm buffer troponin -
both high and low affinity binding sites.
The kinetics of calcium binding to the myoplasm buffer troponin -
both high and low affinity binding sites.
The opening rate of the m gate.
The opening rate of the m gate.
Calculation of the potassium current component of the total channel
current.
Calculation of the potassium current component of the total channel
current.
The kinetics of the m gate.
The kinetics of the m gate.
The kinetics of the transmembrane potential, defined as the sum of
all the sarcolemmal currents and an applied stimulus current.
The kinetics of the transmembrane potential, defined as the sum of
all the sarcolemmal currents and an applied stimulus current.
The kinetics of the calcium ion concentration changes in the various
compartments of the model.
The kinetics of the calcium ion concentration changes in the various
compartments of the model.
Calculate some volume fractions as proportions of the total
myoplasmic volume.
Calculate some volume fractions as proportions of the total
myoplasmic volume.
Calculation of the plateau potassium current.
Calculation of the plateau potassium current.
2003-07-30
2003-07-30
The closing rate of the m gate.
The closing rate of the m gate.
2002-02-28
2002-02-28
Rate constant for switching between mode normal and mode Ca.
Rate constant for switching between mode normal and mode Ca.
The opening rate of the K1 gate.
The opening rate of the K1 gate.
2003-06-04
2003-06-04
The sarcolemmal calcium pump is an additional mechanism for removing
Ca ions from the myoplasm to help maintain a low intracellular
calcium concentration when at rest.
The sarcolemmal calcium pump is an additional mechanism for removing
Ca ions from the myoplasm to help maintain a low intracellular
calcium concentration when at rest.