Several variables have been given cmeta:id's to allow creation of a PCEnv session file.
74
Cardiac Ca2+ Dynamics: The Roles of Ryanodine Receptor Adaptation and Sarcoplasmic Reticulum Load
1168
1149
The total nonspecific calcium activated current.
Lawson
James
Richard
May
Catherine
Lloyd
Lloyd
Catherine
May
Corrected equations.
Calculation of the time-dependent potassium current.
Corrected several equations, variable units and their initial values.
Removed document type definition as this is declared as optional
according to the W3C recommendation.
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.
The kinetics of calcium binding to the myoplasm buffer troponin -
both high and low affinity binding sites.
The potassium permeability of the channel, which depends on the
calcium current component.
James Lawson
Calculation of the Na/K pump current.
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.
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 rate of change of extracellular potassium ion concentration.
Calculation of the plateau potassium current.
The kinetics of the y gate.
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.
The University of Auckland, Bioengineering Research Group
Calculate the calcium flux from the diffusion of calcium out of the
restricted subspace into the myoplasm.
The reversal potential of the channel.
The kinetics of the transmembrane potential, defined as the sum of
all the sarcolemmal currents and an applied stimulus current.
May
Catherine
Lloyd
Catherine
May
Lloyd
John
Rice
Jeremy
Keep track of the concentration of calcium ions bound to high and
low affinity troponin binding sites.
The voltage-dependent activation gate for the fast sodium current -
the m gate.
Catherine
May
Lloyd
Added some initial values from Penny Noble's documentation.
The sodium component of the channel's current.
Calculate the uptake flux into the NSR from the myoplasm.
Lloyd
May
Catherine
The maximal potassium component current.
Calculation of the fast sodium current using the three
Hodkin-Huxley type voltage-dependent gating variables m, h, and j.
2002-05-06
The following equation calculates the reversal potential of the
time-independent potassium current.
The closing rate of the K1 gate.
The University of Auckland
The Bioengineering Research Group
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 main component of the model which defines the action potential.
Calculation of the maximal channel conductance, dependent on
extracellular potassium concentration.
The voltage-dependent inactivation gate for the fast sodium current
- the h gate.
Altered some of the connections.
bdf15
3000
0.2
100000
Lloyd
Catherine
May
Raimond
L
Winslow
The voltage-dependent slow inactivation gate for the fast sodium
current - the j gate.
Calculation of the maximal channel conductance, dependent on
extracellular potassium concentration.
Calculation of the background calcium current.
Raimond
Winslow
L
Lloyd
Catherine
May
calcium dynamics
ryanodine receptor
Xi is the inward rectification parameter and is given by the
following equation.
c.lloyd@auckland.ac.nz
The closing rate of the m gate.
Jeremy
Rice
John
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 opening rate of the K1 gate.
The fast sodium current component contains the differential
equations governing the influx of sodium ions through the cell
surface membrane into the cell.
The Jafri-Rice-Winslow Model for Calcium Regulation in the Ventricular
Myocyte, 1997
Mammalia
Ventricular Myocyte
The kinetics of the m gate.
2003-07-30
2003-06-04
Calculate the leakage flux from the NSR into the myoplasm.
Changed tau_y_calculation after checking mathml using the validator.
2007-05-24T11:52:30+12:00
2002-02-28
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 closing rate of the X gate.
2001-12-07
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.
Calculate the current.
The "open" RyR's are those P_O1 and P_O2 states.
The kinetics of the X gate.
The rate of change of intracellular potassium ion concentration.
Corrected several equations.
The opening rate of the h gate.
The time-independent inactivation gate for the time-dependent
potassium channel.
Rate constant for switching between mode normal and mode Ca.
The potential offset for the channel.
The kinetic equations governing the transitions between the four
states used to model the RyR's.
The voltage-dependent inactivation gate for the L-type calcium
channel - the y gate.
9512016
Jafri
Saleet
M
The calcium release flux from the JSR into the restricted subspace
is governed by the fraction of RyR channels in an open state.
electrophysiology
Ventricular Myocyte
The closing rate of the h gate.
The kinetics of the j gate.
Noble
Penny
J
The rate of change of intracellular sodium ion concentration.
The plateau potassium current component contains the equations which
describe the contribution of a time independent [K]o-insensitive
channel at plateau potentials.
The opening rate of the X gate.
This model has been curated and the output checked against the original paper.
May
Lloyd
Catherine
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 maximal calcium current through the channel.
The descriptions of the rate of change of [Na]i and [K]i are the
same as the LR-II model.
Biophysical Journal
1998-03-01
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 opening rate of the j gate.
The time-independent potassium current.
The reversal potential for the background sodium channel.
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.
Calculation of the potassium current component of the total channel
current.
The reversal potential for the background calcium current.
The voltage- and time-dependent activation gate for the
time-dependent potassium current - the X gate.
Catherine Lloyd
Calculate the translocation flux between the uptake (NSR) and
release (JSR) stores.
The sodium reversal potential.
The maximal sodium component current.
The activation variable.
The channel's reversal potential.
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 opening rate of the m gate.
This is a dummy equation that we simply use to make grabbing the
value in CMISS much easier.
The nonspecific calcium activated current describes a channel which
is activated by calcium ions, but is permeable to only sodium and
potassium ions.
2002-01-04
Calculation of the Na/Ca exchanger current.
Rate constants for state changes in mode normal.
2007-06-22T12:55:26+12:00
The reversal potential of the channel.
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.
2002-02-25
The kinetics of the h gate.
Calculate some volume fractions as proportions of the total
myoplasmic volume.
The potassium component of the channel's current.
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 steady-state approximation for the K1 gating kinetics.
keyword
2001-09-24T00:00:00+00:00
M
Jafri
Saleet
Calculation of the background sodium current.
The calcium pump current.
The kinetics of the calcium ion concentration changes in the various
compartments of the model.
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 closing rate of the j gate.
2001-10-19
Rate constants for state changes in mode Ca (corresponding to
alpha-prime and beta-prime in the JRW paper).
The time constants for the K1 gate are small enough that the gating
variable can be approximated with it's steady-state value.