sodium_ion_channel_cellml.txt

def model sodium_ion_channel as
    def unit millisec as
        unit second {pref: milli};
    enddef;

    def unit per_millisec as
        unit second {pref: milli, expo: -1};
    enddef;

    def unit millivolt as
        unit volt {pref: milli};
    enddef;

    def unit per_millivolt as
        unit millivolt {expo: -1};
    enddef;

    def unit per_millivolt_millisec as
        unit per_millivolt;
        unit per_millisec;
    enddef;

    def unit microA_per_cm2 as
        unit ampere {pref: micro};
        unit metre {pref: centi, expo: -2};
    enddef;

    def unit milliS_per_cm2 as
        unit siemens {pref: milli};
        unit metre {pref: centi, expo: -2};
    enddef;

    def comp environment as
        var V: millivolt {pub: out};
        var t: millisec {pub: out};

        V = sel
            case (t > 5{millisec}) and (t < 15{millisec}):
                0.0{millivolt};
            otherwise:
                -85.0{millivolt};
        endsel;
    enddef;

    def group as encapsulation for
        comp sodium_channel incl
            comp sodium_channel_m_gate;
            comp sodium_channel_h_gate;
        endcomp;
    enddef;

    def comp sodium_channel as
        var V: millivolt {pub: in, priv: out};
        var t: millisec {pub: in, priv: out};
        var m: dimensionless {priv: in};
        var h: dimensionless {priv: in};
        var g_Na: milliS_per_cm2 {init: 120};
        var E_Na: millivolt {init: 35};
        var Na_conductance: milliS_per_cm2 {pub: out};
        var i_Na: microA_per_cm2 {pub: out};

        Na_conductance = g_Na*pow(m, 3{dimensionless})*h;
        i_Na = Na_conductance*(V-E_Na);
    enddef;

    def comp sodium_channel_m_gate as
        var V: millivolt {pub: in};
        var t: millisec {pub: in};
        var alpha_m: per_millisec;
        var beta_m: per_millisec;
        var m: dimensionless {init: 0.05, pub: out};

        alpha_m = -0.1{per_millivolt_millisec}*(V+50{millivolt})/(exp(-(V+50{millivolt})/10{millivolt})-1{dimensionless});
        beta_m = 4{per_millisec}*exp(-(V+75{millivolt})/18{millivolt});
        ode(m, t) = alpha_m*(1{dimensionless}-m)-beta_m*m;
    enddef;

    def comp sodium_channel_h_gate as
        var V: millivolt {pub: in};
        var t: millisec {pub: in};
        var alpha_h: per_millisec;
        var beta_h: per_millisec;
        var h: dimensionless {init: 0.6, pub: out};

        alpha_h = 0.07{per_millisec}*exp(-(V+75{millivolt})/20{millivolt});
        beta_h = 1{per_millisec}/(exp(-(V+45{millivolt})/10{millivolt})+1{dimensionless});
        ode(h, t) = alpha_h*(1{dimensionless}-h)-beta_h*h;
    enddef;

    def map between sodium_channel and environment for
        vars V and V;
        vars t and t;
    enddef;

    def map between sodium_channel and sodium_channel_m_gate for
        vars V and V;
        vars t and t;
        vars m and m;
    enddef;

    def map between sodium_channel and sodium_channel_h_gate for
        vars V and V;
        vars t and t;
        vars h and h;
    enddef;
enddef;