Markovian model for single-channel recordings of Ik_1 in ventricular cells (Matsuoka et al 2003)

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Accession:62676
The interaction between many currents in a cardiac ventricular model are examined in this paper. One of the main contributions come from a current called IK_1. An XPP version of this model was supplied by Hsieng-Jung Lai, Jiun-Shian Wu, Sheng-Nan Wu, Ruey J. Sung, Han-Dong Chang. Please see paper and model for more and details.
Reference:
1 . Matsuoka S, Sarai N, Kuratomi S, Ono K, Noma A (2003) Role of individual ionic current systems in ventricular cells hypothesized by a model study. Jpn J Physiol 53:105-23 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Channel/Receptor;
Brain Region(s)/Organism:
Cell Type(s):
Channel(s): I K;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: XPP;
Model Concept(s): Ion Channel Kinetics; Heart disease; Cardiac pacemaking; Markov-type model;
Implementer(s): Wu, Sheng-Nan [snwu at mail.ncku.edu.tw]; Chang, Han-Dong; Wu, Jiun-Shian [coolneon at gmail.com]; Sung, Ruey J ; Lai, Hsing-Jung ;
Search NeuronDB for information about:  I K;
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ik1
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Ik_1_sim.ode
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# Markovian model for single-channel recrodings of Ik_1 in ventricular cells 
# from Matsuoka et al., Role of individual ionic current systems in ventricular cells
# hypothesized by a model study. Jpn J Physiol 2003 53:105-123
#This model is contributed by  Hsieng-Jung Lai, Jiun-Shian Wu, Sheng-Nan Wu, Ruey J. Sung, Han-Dong Chang.

# Initial values
init b41=1, b31=0, b21=0, b11=0, o1=0
init b40=0, b30=0, b20=0, b10=0, o0=0

# Voltage clamp protocols
par vhold=-50, vtest_1=-120, vtest_2=-50
par ton=30, toff=430, toff_r=500
v = vhold+heav(t-ton)*heav(toff-t)*(vtest_1-vhold)+heav(t-toff)*heav(toff_r-t)*(vtest_2-vhold)

# Default parameters
number R=8.3143, Temp=310, Fara=96.4867

# Values of the model parameters
par Ek=-80 ,ko=5.4

# Expressions
alphay=1/(8000*exp((v-ek-97)/8.5)+7*exp((v-ek-97)/300))
betay=1/(0.00014*exp(-(v-ek-97)/9.1)+0.2*exp(-(v-ek-97)/500))
myu=0.75*exp(0.035*(v-ek-10))/(1+exp(0.015*(v-ek-140)))
lambda=3*exp(-0.048*(v-ek-10))*(1+exp(0.064*(v-ek-38)))/(1+exp(0.03*(v-ek-70)))

#gk1=0.1*(ko/5.4)^0.4
#for SA node cell

gk1=151.5*(ko/5.4)^0.4
#for ventricular cell

# Markov expressions:
o0'=-o0*(4*myu+betay)+lambda*b10+o1*alphay
b10'=-b10*(lambda+3*myu+betay)+4*myu*o0+2*lambda*b20+alphay*b11
b20'=-b20*(2*lambda+2*myu+betay)+3*myu*b10+3*lambda*b30+alphay*b21
b30'=-b30*(3*lambda+myu+betay)+2*myu*b20+4*lambda*b40+alphay*b31
b40'=-b40*(4*lambda+betay)+myu*b30+alphay*b41
o1'=-o1*(alphay+4*myu)+betay*o0+lambda*b11
b11'=-b11*(alphay+lambda+3*myu)+betay*b10+4*myu*o1+2*lambda*b21
b21'=-b21*(alphay+2*lambda+2*myu)+betay*b20+3*myu*b11+3*lambda*b31
b31'=-b31*(alphay+3*lambda+myu)+betay*b30+2*myu*b21+4*lambda*b41
b41'=-b41*(alphay+4*lambda)+betay*b40+myu*b31

aux Ik1=gk1*(v-ek)*(o0)


@ meth=Euler, dt=.01, total=500
@ yp=ik1, yhi=1, ylo=-3, xlo=0, xhi=500, bound=5000000

done

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