Optimised version of Kca1_1

dbbs_catalogue/mod/Kca1_1.mod

@@ -1,101 +1,65 @@
 TITLE Large conductance Ca2+ activated K+ channel mslo
 
 COMMENT
-
 Parameters from Cox et al. (1987) J Gen Physiol 110:257-81 (patch 1).
 
-Current Model Reference: Anwar H, Hong S, De Schutter E (2010) Controlling Ca2+-activated K+ channels with models of Ca2+ buffering in Purkinje cell. Cerebellum*
+Current Model Reference: Anwar H, Hong S, De Schutter E (2010) Controlling
+Ca2+-activated K+ channels with models of Ca2+ buffering in Purkinje cell.
+Cerebellum*
 
 *Article available as Open Access
 
 PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/20981513
 
-
 Written by Sungho Hong, Okinawa Institute of Science and Technology, March 2009.
 Contact: Sungho Hong (shhong@oist.jp)
-
-
 ENDCOMMENT
 
 NEURON {
   SUFFIX Kca1_1
   USEION k READ ek WRITE ik
   USEION ca READ cai
-  RANGE g, gbar, ik
-
+  RANGE gbar
 }
 
 UNITS {
-    (mV) = (millivolt)
-    (S) = (siemens)
+    (mV)    = (millivolt)
+    (S)     = (siemens)
     (molar) = (1/liter)
-    (mM) = (millimolar)
+    (mM)    = (millimolar)
 }
 
 CONSTANT {
   FARADAY = 96.520
-  R = 8.3134 : gas constant (J/K.mol)
-  q10 = 3
+  R       = 8.3134 : gas constant (J/K.mol)
+  q10     = 3
 }
 
 PARAMETER {
-    v            (mV)
-    celsius      (degC)
+    v           (mV)
+    celsius     (degC)
     gbar = 0.01 (S/cm2)
 
-    Qo = 0.73
+    Qo =  0.73
     Qc = -0.67
 
-    k1 = 1.0e3 (/mM)
-    onoffrate = 1 (/ms)
+    k1        = 1000.0 (/mM)
+    onoffrate =    1.0 (/ms)
 
-    L0 = 1806
-    Kc = 11.0e-3 (mM)
-    Ko = 1.1e-3 (mM)
+    Kc =    11.0e-3 (mM)
+    Ko =     1.1e-3 (mM)
 
-    pf0 = 2.39e-3  (/ms)
-    pf1 = 7.0e-3  (/ms)
-    pf2 = 40e-3   (/ms)
-    pf3 = 295e-3  (/ms)
-    pf4 = 557e-3  (/ms)
+    pf0 =    2.39e-3  (/ms)
+    pf1 =    7.0e-3   (/ms)
+    pf2 =   40.0e-3   (/ms)
+    pf3 =  295.0e-3   (/ms)
+    pf4 =  557.0e-3   (/ms)
 
-    pb0 = 3936e-3 (/ms)
-    pb1 = 1152e-3 (/ms)
-    pb2 = 659e-3  (/ms)
-    pb3 = 486e-3  (/ms)
-    pb4 = 92e-3  (/ms)
-}
-
-ASSIGNED {
-    g            (S/cm2)
-    : rates
-    c01    (/ms)
-    c12    (/ms)
-    c23    (/ms)
-    c34    (/ms)
-    o01    (/ms)
-    o12    (/ms)
-    o23    (/ms)
-    o34    (/ms)
-    f0     (/ms)
-    f1     (/ms)
-    f2     (/ms)
-    f3     (/ms)
-    f4     (/ms)
-
-    c10    (/ms)
-    c21    (/ms)
-    c32    (/ms)
-    c43    (/ms)
-    o10    (/ms)
-    o21    (/ms)
-    o32    (/ms)
-    o43    (/ms)
-    b0     (/ms)
-    b1     (/ms)
-    b2     (/ms)
-    b3     (/ms)
-    b4     (/ms)
+    pb0 = 3936.0e-3  (/ms)
+    pb1 = 1152.0e-3  (/ms)
+    pb2 =  659.0e-3  (/ms)
+    pb3 =  486.0e-3  (/ms)
+    pb4 =   92.0e-3  (/ms)
 }
 
 STATE {
@@ -113,69 +77,75 @@ STATE {
 
 BREAKPOINT {
     SOLVE activation METHOD sparse
-    g = gbar * (O0 + O1 + O2 + O3 + O4)
-    ik = g * (v - ek)
+    LOCAL g
+    g  = gbar*(O0 + O1 + O2 + O3 + O4)
+    ik = g*(v - ek)
 }
 
 INITIAL {
-    rates(v, celsius, cai)
     SOLVE activation STEADYSTATE sparse
 }
 
 KINETIC activation {
-    rates(v, celsius, cai)
-    ~ C0 <-> C1      (c01,c10)
-    ~ C1 <-> C2      (c12,c21)
-    ~ C2 <-> C3      (c23,c32)
-    ~ C3 <-> C4      (c34,c43)
-    ~ O0 <-> O1      (o01,o10)
-    ~ O1 <-> O2      (o12,o21)
-    ~ O2 <-> O3      (o23,o32)
-    ~ O3 <-> O4      (o34,o43)
-    ~ C0 <-> O0      (f0 , b0)
-    ~ C1 <-> O1      (f1 , b1)
-    ~ C2 <-> O2      (f2 , b2)
-    ~ C3 <-> O3      (f3 , b3)
-    ~ C4 <-> O4      (f4 , b4)
-
-CONSERVE C0 + C1 + C2 + C3 + C4 + O0 + O1 + O2 + O3 + O4 = 1
-}
-
-PROCEDURE rates(v(mV), celsius, ca (mM)) {
-    LOCAL qt, alpha, beta
-
-    qt = q10^((celsius-23)/10)
-
-    c01 = 4*ca*k1*onoffrate*qt
-    c12 = 3*ca*k1*onoffrate*qt
-    c23 = 2*ca*k1*onoffrate*qt
-    c34 = 1*ca*k1*onoffrate*qt
-    o01 = 4*ca*k1*onoffrate*qt
-    o12 = 3*ca*k1*onoffrate*qt
-    o23 = 2*ca*k1*onoffrate*qt
-    o34 = 1*ca*k1*onoffrate*qt
-
-    c10 = 1*Kc*k1*onoffrate*qt
-    c21 = 2*Kc*k1*onoffrate*qt
-    c32 = 3*Kc*k1*onoffrate*qt
-    c43 = 4*Kc*k1*onoffrate*qt
-    o10 = 1*Ko*k1*onoffrate*qt
-    o21 = 2*Ko*k1*onoffrate*qt
-    o32 = 3*Ko*k1*onoffrate*qt
-    o43 = 4*Ko*k1*onoffrate*qt
-
-    alpha = exp(Qo*FARADAY*v/R/(273.15 + celsius))
-    beta  = exp(Qc*FARADAY*v/R/(273.15 + celsius))
-
-    f0  = pf0*alpha*qt
-    f1  = pf1*alpha*qt
-    f2  = pf2*alpha*qt
-    f3  = pf3*alpha*qt
-    f4  = pf4*alpha*qt
-
-    b0  = pb0*beta*qt
-    b1  = pb1*beta*qt
-    b2  = pb2*beta*qt
-    b3  = pb3*beta*qt
-    b4  = pb4*beta*qt
+    LOCAL c01, c12, c23, c34
+    LOCAL o01, o12, o23, o34
+    LOCAL c10, c21, c32, c43
+    LOCAL o10, o21, o32, o43
+
+    LOCAL f0, f1, f2, f3, f4
+    LOCAL b0, b1, b2, b3, b4
+
+    LOCAL qt, alpha, beta, k1p, b
+
+    qt    = q10^(0.1*(celsius - 23.0))
+    k1p   = k1*onoffrate*qt
+    b     = FARADAY*v/(R*(273.15 + celsius))
+    alpha = qt*exp(Qo*b)
+    beta  = qt*exp(Qc*b)
+
+    c01 = 4*ca*k1p
+    c12 = 3*ca*k1p
+    c23 = 2*ca*k1p
+    c34 = 1*ca*k1p
+    o01 = 4*ca*k1p
+    o12 = 3*ca*k1p
+    o23 = 2*ca*k1p
+    o34 = 1*ca*k1p
+
+    c10 = 1*Kc*k1p
+    c21 = 2*Kc*k1p
+    c32 = 3*Kc*k1p
+    c43 = 4*Kc*k1p
+    o10 = 1*Ko*k1p
+    o21 = 2*Ko*k1p
+    o32 = 3*Ko*k1p
+    o43 = 4*Ko*k1p
+
+    f0  = pf0*alpha
+    f1  = pf1*alpha
+    f2  = pf2*alpha
+    f3  = pf3*alpha
+    f4  = pf4*alpha
+
+    b0  = pb0*beta
+    b1  = pb1*beta
+    b2  = pb2*beta
+    b3  = pb3*beta
+    b4  = pb4*beta
+
+    ~ C0 <-> C1  (c01, c10)
+    ~ C1 <-> C2  (c12, c21)
+    ~ C2 <-> C3  (c23, c32)
+    ~ C3 <-> C4  (c34, c43)
+    ~ O0 <-> O1  (o01, o10)
+    ~ O1 <-> O2  (o12, o21)
+    ~ O2 <-> O3  (o23, o32)
+    ~ O3 <-> O4  (o34, o43)
+    ~ C0 <-> O0  (f0,   b0)
+    ~ C1 <-> O1  (f1,   b1)
+    ~ C2 <-> O2  (f2,   b2)
+    ~ C3 <-> O3  (f3,   b3)
+    ~ C4 <-> O4  (f4,   b4)
+
+    CONSERVE C0 + C1 + C2 + C3 + C4 + O0 + O1 + O2 + O3 + O4 = 1
 }