// FILE IN USE 05/17/2005 -- present.
// Changes to previous version of 01/05:
// 1. HCN channels rebuilt based on Chan et al (2004), J Neurosci 24: 9921-32.
//genesis
float xmin = -0.2
float xmax = 0.1
int xdivs = 299
float dx = (xmax - xmin)/xdivs
int xdivs_interp = 6000
float dx_interp = (xmax - xmin)/xdivs_interp
float x
int i
//==================================================================
// Tab channel descriptions for GP neuron modeling
// Created by J. Hanson
// edited 10-02
// Updated by J. Edgerton, 9/2003 --
//==================================================================
//==================================================================
// Fast Na channel
// Activation and fast inactivation made to replicate resurgent
// sodium current from Raman & Bean.
// Slow inactivation gate added by J. Edgerton, 2004.
// Support for voltage-dependent Z-gate by Cengiz Gunay, 2004
//==================================================================
function make_Na_fast_GP_Zgate
if ({exists Na_fast_GP})
return
end
create tabchannel Na_fast_GP
float mpower = 3
setfield Na_fast_GP Ek {ENa} Gbar {G_Na_fast_GP} Ik 0 Gk 0\
Xpower {mpower} Ypower 1 Zpower 1
// Activation & Deactivation
float Vhalfm = {Vhalfm_NaF}
float Km = {Km_NaF}
float taummax = {taummax_NaF} // 0.000028 //0.00010
float taummin = {taummin_NaF} // 0.00000157 //0.00002
float Ktau1 = 0.02
float Ktau2 = 0.02
float V0m, minf, taum
V0m = {Vhalfm} + ({Km} * {log {(1 / {pow 0.5 {1/{mpower}}}) - 1}})
echo "Na_fast V0m: " {V0m}
call Na_fast_GP TABCREATE X {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
minf = 1 / (1 + {exp {({V0m} - x) / {Km} }})
taum = {taummin} + (({taummax} - {taummin}) / ({exp { (x - {V0m}) / {Ktau1} } } + {exp {({V0m} - x) / {Ktau2} }}))
setfield Na_fast_GP X_A->table[{i}] {taum}
setfield Na_fast_GP X_B->table[{i}] {minf}
x = x + dx
end
tweaktau Na_fast_GP X
call Na_fast_GP TABFILL X {xdivs_interp} 0
setfield Na_fast_GP X_A->calc_mode {NO_INTERP}
setfield Na_fast_GP X_B->calc_mode {NO_INTERP}
// Fast Inactivation
float V0h = {V0h_NaF}
float tauhV0 = {tauhV0_NaF}
float Kh = {Kh_NaF} // -0.003848
float tauhmax = {tauhmax_NaF} // 0.004
float tauhmin = {tauhmin_NaF} // 0.0002
float Ktau1h = 0.005
float Ktau2h = 0.01
float hinf, tauh
call Na_fast_GP TABCREATE Y {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
hinf = 1 / (1 + {exp {({V0h} - x) / {Kh} }})
tauh = {tauhmin} + (({tauhmax} - {tauhmin}) / ({exp { (x - {tauhV0}) / {Ktau1h} } } + {exp {({tauhV0} - x) / {Ktau2h} }}))
setfield Na_fast_GP Y_A->table[{i}] {tauh}
setfield Na_fast_GP Y_B->table[{i}] {hinf}
x = x + dx
end
tweaktau Na_fast_GP Y
call Na_fast_GP TABFILL Y {xdivs_interp} 0
setfield Na_fast_GP Y_A->calc_mode {NO_INTERP}
setfield Na_fast_GP Y_B->calc_mode {NO_INTERP}
// Slow Inactivation
// Equations & params from Spampanato et al, 2003, except that
// tausmin added to prevent segmentation faults due to
// excessively small time constants at voltage extremes.
float V0s = {V0s_NaF}
float tausV0 = {V0s_NaF}
float Ks = {Ks_NaF}
float mins = {mins_NaF}
float Ktaus1 = {Ktaus1_NaF}
float Ktaus2 = {Ktaus2_NaF}
float tausmax = {tausmax_NaF}
float tausmin = {tausmin_NaF}
float sinf, taus
call Na_fast_GP TABCREATE Z {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
sinf = {mins} + ((1-{mins}) / (1 + {exp {({V0s} - x) / {Ks} }}))
taus = tausmin + ({tausmax} - {tausmin}) / ({exp {({tausV0} - x) / {Ktaus1}}} + {exp {(x - {tausV0}) / {Ktaus2}}})
setfield Na_fast_GP Z_A->table[{i}] {taus}
setfield Na_fast_GP Z_B->table[{i}] {sinf}
x = x + dx
end
tweaktau Na_fast_GP Z
call Na_fast_GP TABFILL Z {xdivs_interp} 0
setfield Na_fast_GP Z_A->calc_mode {NO_INTERP}
setfield Na_fast_GP Z_B->calc_mode {NO_INTERP}
setfield Na_fast_GP Z_conc 0 // Z-gate voltage-dependent
end
//==================================================================
// Fast Na channel
// Activation and fast inactivation made to replicate resurgent
// sodium current from Raman & Bean.
// Slow inactivation gate added by J. Edgerton, 2004.
// Support for voltage-dependent Z-gate by Cengiz Gunay, 2004
// Populates all table entries from the original equation,
// rather than using TABFILL (for testing purposes).
//==================================================================
function make_Na_fast_GP_Zgate_nofill
if ({exists Na_fast_GP})
return
end
create tabchannel Na_fast_GP
float mpower = 3
setfield Na_fast_GP Ek {ENa} Gbar {G_Na_fast_GP} Ik 0 Gk 0\
Xpower {mpower} Ypower 1 Zpower 1
// Activation & Deactivation
float Vhalfm = {Vhalfm_NaF}
float Km = {Km_NaF}
float taummax = {taummax_NaF} // 0.000028 //0.00010
float taummin = {taummin_NaF} // 0.00000157 //0.00002
float Ktau1 = 0.02
float Ktau2 = 0.02
float V0m, minf, taum
V0m = {Vhalfm} + ({Km} * {log {(1 / {pow 0.5 {1/{mpower}}}) - 1}})
echo "Na_fast V0m: " {V0m}
call Na_fast_GP TABCREATE X {xdivs_interp} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs_interp}; i = i + 1)
minf = 1 / (1 + {exp {({V0m} - x) / {Km} }})
taum = {taummin} + (({taummax} - {taummin}) / ({exp { (x - {V0m}) / {Ktau1} } } + {exp {({V0m} - x) / {Ktau2} }}))
setfield Na_fast_GP X_A->table[{i}] {taum}
setfield Na_fast_GP X_B->table[{i}] {minf}
x = x + dx_interp
end
tweaktau Na_fast_GP X
//call Na_fast_GP TABFILL X {xdivs_interp} 0
setfield Na_fast_GP X_A->calc_mode {NO_INTERP}
setfield Na_fast_GP X_B->calc_mode {NO_INTERP}
// Fast Inactivation
float V0h = {V0h_NaF}
float tauhV0 = {tauhV0_NaF}
float Kh = {Kh_NaF} // -0.003848
float tauhmax = {tauhmax_NaF} // 0.004
float tauhmin = {tauhmin_NaF} // 0.0002
float Ktau1h = 0.005
float Ktau2h = 0.01
float hinf, tauh
call Na_fast_GP TABCREATE Y {xdivs_interp} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs_interp}; i = i + 1)
hinf = 1 / (1 + {exp {({V0h} - x) / {Kh} }})
tauh = {tauhmin} + (({tauhmax} - {tauhmin}) / ({exp { (x - {tauhV0}) / {Ktau1h} } } + {exp {({tauhV0} - x) / {Ktau2h} }}))
setfield Na_fast_GP Y_A->table[{i}] {tauh}
setfield Na_fast_GP Y_B->table[{i}] {hinf}
x = x + dx_interp
end
tweaktau Na_fast_GP Y
//call Na_fast_GP TABFILL Y {xdivs_interp} 0
setfield Na_fast_GP Y_A->calc_mode {NO_INTERP}
setfield Na_fast_GP Y_B->calc_mode {NO_INTERP}
// Slow Inactivation
// Equations & params from Spampanato et al, 2003, except that
// tausmin added to prevent segmentation faults due to
// excessively small time constants at voltage extremes.
float V0s = {V0s_NaF}
float tausV0 = {V0s_NaF}
float Ks = {Ks_NaF}
float mins = {mins_NaF}
float Ktaus1 = {Ktaus1_NaF}
float Ktaus2 = {Ktaus2_NaF}
float tausmax = {tausmax_NaF}
float tausmin = {tausmin_NaF}
float sinf, taus
call Na_fast_GP TABCREATE Z {xdivs_interp} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs_interp}; i = i + 1)
sinf = {mins} + ((1-{mins}) / (1 + {exp {({V0s} - x) / {Ks} }}))
taus = tausmin + ({tausmax} - {tausmin}) / ({exp {({tausV0} - x) / {Ktaus1}}} + {exp {(x - {tausV0}) / {Ktaus2}}})
setfield Na_fast_GP Z_A->table[{i}] {taus}
setfield Na_fast_GP Z_B->table[{i}] {sinf}
x = x + dx_interp
end
tweaktau Na_fast_GP Z
//call Na_fast_GP TABFILL Z {xdivs_interp} 0
setfield Na_fast_GP Z_A->calc_mode {NO_INTERP}
setfield Na_fast_GP Z_B->calc_mode {NO_INTERP}
setfield Na_fast_GP Z_conc 0 // Z-gate voltage-dependent
end
//==================================================================
// Fast Na channel
// Activation and fast inactivation made to replicate resurgent
// sodium current from Raman & Bean.
// Slow inactivation gate added by J. Edgerton, 2004.
// Adapted to use the tab2Dchannel instead of Z-gate by C. Gunay, Jan 2006.
//==================================================================
function make_Na_fast_GP_tab2D
if ({exists Na_fast_GP})
return
end
create tab2Dchannel Na_fast_GP
float mpower = 3
setfield Na_fast_GP Ek {ENa} Gbar {G_Na_fast_GP} Ik 0 Gk 0\
Xpower {mpower} Ypower 1 Zpower 1
// Activation & Deactivation
float Vhalfm = {Vhalfm_NaF}
float Km = {Km_NaF}
float taummax = {taummax_NaF} // 0.000028 //0.00010
float taummin = {taummin_NaF} // 0.00000157 //0.00002
float Ktau1 = 0.02
float Ktau2 = 0.02
float V0m, minf, taum
V0m = {Vhalfm} + ({Km} * {log {(1 / {pow 0.5 {1/{mpower}}}) - 1}})
echo "Na_fast V0m: " {V0m}
// Special use of 2D table as a 1D table
call Na_fast_GP TABCREATE X 0 0 0 {xdivs_interp} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs_interp}; i = i + 1)
minf = 1 / (1 + {exp {({V0m} - x) / {Km} }})
taum = {taummin} + (({taummax} - {taummin}) / ({exp { (x - {V0m}) / {Ktau1} } } + {exp {({V0m} - x) / {Ktau2} }}))
// tweaktau doesn't apply to tab2D, we fill tables directly with A & B
setfield Na_fast_GP X_A->table[0][{i}] {({minf} / {taum})}
setfield Na_fast_GP X_B->table[0][{i}] {(1 / {taum})}
x = x + dx_interp
end
/*setfield Na_fast_GP X_A->calc_mode {NO_INTERP}
setfield Na_fast_GP X_B->calc_mode {NO_INTERP}*/
// Voltage dependent gate
setfield Na_fast_GP Xindex VOLT_INDEX
// Fast Inactivation
float V0h = {V0h_NaF}
float tauhV0 = {tauhV0_NaF}
float Kh = {Kh_NaF} // -0.003848
float tauhmax = {tauhmax_NaF} // 0.004
float tauhmin = {tauhmin_NaF} // 0.0002
float Ktau1h = 0.005
float Ktau2h = 0.01
float hinf, tauh
call Na_fast_GP TABCREATE Y 0 0 0 {xdivs_interp} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs_interp}; i = i + 1)
hinf = 1 / (1 + {exp {({V0h} - x) / {Kh} }})
tauh = {tauhmin} + (({tauhmax} - {tauhmin}) / ({exp { (x - {tauhV0}) / {Ktau1h} } } + {exp {({tauhV0} - x) / {Ktau2h} }}))
setfield Na_fast_GP Y_A->table[0][{i}] {({hinf} / {tauh})}
setfield Na_fast_GP Y_B->table[0][{i}] {(1 / {tauh})}
x = x + dx_interp
end
/*setfield Na_fast_GP Y_A->calc_mode {NO_INTERP}
setfield Na_fast_GP Y_B->calc_mode {NO_INTERP}*/
setfield Na_fast_GP Yindex VOLT_INDEX
// Slow Inactivation
// Equations & params from Spampanato et al, 2003, except that
// tausmin added to prevent segmentation faults due to
// excessively small time constants at voltage extremes.
float V0s = {V0s_NaF}
float tausV0 = {V0s_NaF}
float Ks = {Ks_NaF}
float mins = {mins_NaF}
float Ktaus1 = {Ktaus1_NaF}
float Ktaus2 = {Ktaus2_NaF}
float tausmax = {tausmax_NaF}
float tausmin = {tausmin_NaF}
float sinf, taus
call Na_fast_GP TABCREATE Z 0 0 0 {xdivs_interp} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs_interp}; i = i + 1)
sinf = {mins} + ((1-{mins}) / (1 + {exp {({V0s} - x) / {Ks} }}))
taus = tausmin + ({tausmax} - {tausmin}) / ({exp {({tausV0} - x) / {Ktaus1}}} + {exp {(x - {tausV0}) / {Ktaus2}}})
setfield Na_fast_GP Z_A->table[0][{i}] {({sinf} / {taus})}
setfield Na_fast_GP Z_B->table[0][{i}] {(1 / {taus})}
x = x + dx_interp
end
/*setfield Na_fast_GP Z_A->calc_mode {NO_INTERP}
setfield Na_fast_GP Z_B->calc_mode {NO_INTERP}*/
// Z-gate voltage-dependent
setfield Na_fast_GP Zindex VOLT_INDEX
end
//==================================================================
// persistent Na channel
// Based on Magistretti & Alonso (1999), JGP 114:491-509
// and Magistretti & Alonso (2002), JGP 120: 855-873.
// Created by J.R. Edgerton, 03/2004
// Modified 10/2004 by JRE: add z-gate slow inactivation, improve
// model's y-gate intermediate inactivation.
//==================================================================
function make_Na_slow_GP
if ({exists Na_slow_GP})
return
end
create tabchannel Na_slow_GP
float mpower = 3
setfield Na_slow_GP Ek {ENa} Gbar {G_Na_slow_GP} Ik 0 Gk 0 \
Xpower {mpower} Ypower 1 Zpower 1
float q10 = 3 // = Q10^((32-22)/10) with Q10 = 3.
// *** Activation & Deactivation (m-gate)
float Km = 0.0057 // with mpower = 3, this makes actual K = 0.0045.
float Vhalfm = {Vhalfm_NaP} // -0.053 according to Magistretti & Alonso
float Ktaum = 0.0144
float V0taum = -0.0416
float alp0 = 2130 // 0.00213
float bet0 = 2460
float V0m = {Vhalfm} + ({Km} * {log {(1 / {pow 0.5 {1/{mpower}}}) - 1}})
echo "Na_slow V0m: " {V0m}
float alpham, betam, taum, minf
call Na_slow_GP TABCREATE X {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
alpham = alp0 * {exp {(x - {V0taum}) / {Ktaum}}} * {q10}
betam = bet0 * {exp {({V0taum} - x) / {Ktaum}}} * {q10}
minf = 1 / (1 + {exp {({V0m} - x) / {Km} }})
taum = 1 / ({alpham} + {betam})
setfield Na_slow_GP X_A->table[{i}] {taum}
setfield Na_slow_GP X_B->table[{i}] {minf}
x = x + dx
end
tweaktau Na_slow_GP X
call Na_slow_GP TABFILL X {xdivs_interp} 0
setfield Na_slow_GP X_A->calc_mode {NO_INTERP}
setfield Na_slow_GP X_B->calc_mode {NO_INTERP}
// *** Fast / Intermediate Inactivation (h-gate)
float hmin = {hmin_NaP} // 0.154
float V0h = {V0h_NaP} // -0.057
float Kh = {Kh_NaP} // -0.004
float V0tauh = -0.034
float Ktauh1 = -0.026
float Ktauh2 = -0.0319
float tauhmin = 0.030
float tauhmax = 0.051
float tauh, hinf
call Na_slow_GP TABCREATE Y {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
hinf = {hmin} + ((1 - {hmin}) / (1 + {exp {({V0h} - x) / {Kh} }}))
tauh = ({tauhmin} + (({tauhmax} - {tauhmin}) / ({exp {(x - {V0tauh}) / {Ktauh1}}} + {exp {({V0tauh} - x) / {Ktauh2}}}))) / {q10}
setfield Na_slow_GP Y_A->table[{i}] {tauh}
setfield Na_slow_GP Y_B->table[{i}] {hinf}
x = x + dx
end
tweaktau Na_slow_GP Y
call Na_slow_GP TABFILL Y {xdivs_interp} 0
setfield Na_slow_GP Y_A->calc_mode {NO_INTERP}
setfield Na_slow_GP Y_B->calc_mode {NO_INTERP}
// *** Slow Inactivation (s-gate)
float Ks = -0.0049
float V0s = {V0s_NaP}
float Aalpha = -2.88 //units of /volt/sec
float Balpha = -0.049 //units of /sec
float Kalpha = 0.00463 //units of volt
float Abeta = {Abeta_NaP} //6.94 //units of /volt/sec
float Bbeta = {Bbeta_NaP} // 0.447 //units of /sec
float Kbeta = -0.00263 //units of volt
float alphas, betas, taus, sinf
call Na_slow_GP TABCREATE Z {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
alphas = {q10} * (({Aalpha} * x) + {Balpha}) / (1 - {exp {((x + ({Balpha} / {Aalpha})) / {Kalpha})}})
betas = {q10} * (({Abeta} * x) + {Bbeta}) / (1 - {exp {((x + ({Bbeta} / {Abeta})) / {Kbeta})}})
taus = 1 / ({alphas} + {betas})
sinf = 1 / (1 + {exp {({V0s} - x) / {Ks} }})
setfield Na_slow_GP Z_A->table[{i}] {taus}
setfield Na_slow_GP Z_B->table[{i}] {sinf}
x = x + dx
end
tweaktau Na_slow_GP Z
call Na_slow_GP TABFILL Z {xdivs_interp} 0
setfield Na_slow_GP Z_A->calc_mode {NO_INTERP}
setfield Na_slow_GP Z_B->calc_mode {NO_INTERP}
setfield Na_slow_GP Z_conc 0 // Z-gate voltage-dependent
end
//==================================================================
// Kdr Kv2
// (Kv2.1) slow activating
// Created based on GP data:
// Baranuskas, Tkatch and Surmeier
// 1999, J Neurosci 19(15):6394-6404
//==================================================================
function make_Kv2_GP
if (({exists Kv2_GP}))
return
end
create tabchannel Kv2_GP
float npower = {npower_Kv2} //4
setfield Kv2_GP Ek {EK} Gbar {G_Kv2_GP} Ik 0 Gk 0\
Xpower {npower} Ypower 1 Zpower 0
float taunmax = {taunmax_Kv2} // 0.03
float taunmin = {taunmin_Kv2} // 0.0001
float Kn = {Kn_Kv2}
float Vhalfn = {Vhalfn_Kv2} // True Vhalf for channel activation
float K1tau = -0.01391
float K2tau = -0.02174
float V0n, ninf, taun, alpha, beta
V0n = {Vhalfn} + ({Kn} * {log {(1 / {pow 0.5 {1/{npower}}}) - 1}})
echo "Kv2 V0n: " {V0n}
//V0n is Vhalf for each individual n gate.
call Kv2_GP TABCREATE X {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
ninf = 1 / (1 + {exp { ({V0n} - x) / {Kn} } } )
taun = {taunmin} + (({taunmax} - {taunmin}) / ({exp { ({V0n} - x) / {K1tau} } } + {exp {-({V0n} - x) / {K2tau} }}))
setfield Kv2_GP X_A->table[{i}] {taun}
setfield Kv2_GP X_B->table[{i}] {ninf}
/* Manual table contruction bypassing tweaktau:
alpha = {ninf} / {taun}
beta = {(1 / {taun}) - {alpha}}
setfield Kv2_GP X_A->table[{i}] {alpha}
setfield Kv2_GP X_B->table[{i}] {1 / {taun}}
*/
x = x + dx
end
tweaktau Kv2_GP X
call Kv2_GP TABFILL X {xdivs_interp} 0
setfield Kv2_GP X_A->calc_mode {NO_INTERP}
setfield Kv2_GP X_B->calc_mode {NO_INTERP}
float Kh = 0.010
float V0h = -0.02
float hmin = {hmin_Kv2} // 0.2
float tauhmax = 3.4
float tauhmin = 3.4
float tauhK = 0.010
float tauhV0 = 0 //-0.070
float hinf, tauh
call Kv2_GP TABCREATE Y {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
hinf = {hmin} + ((1 - {hmin}) / (1 + {exp {(x - {V0h}) / {Kh} }}))
tauh = {{tauhmax}-{tauhmin}} / (1 + {exp {(x - {tauhV0}) / {tauhK} }}) + {tauhmin}
setfield Kv2_GP Y_A->table[{i}] {tauh}
setfield Kv2_GP Y_B->table[{i}] {hinf}
x = x + dx
end
tweaktau Kv2_GP Y
call Kv2_GP TABFILL Y {xdivs_interp} 0
setfield Kv2_GP Y_A->calc_mode {NO_INTERP}
setfield Kv2_GP Y_B->calc_mode {NO_INTERP}
end
//==================================================================
// Kdr Kv3
// (Kv3.1/3.4 heteromultimers) fast activating,
// incompletely inactivating.
// From Surmeier's kv3sur.mod NEURON mechanism
// written by Josh Held
// Adapted to genesis by J.R. Edgerton, 2003
// Modified to reflect new data in
// Baranauskas et al (2003) by J.R. Edgerton, 2004.
// Baranauskas, Tkatch and Surmeier
// 1999, J Neurosci 19(15):6394-6404
// Baranauskas, Tkatch, Nagata, Yeh & Surmeier 2003.
// Nat Neurosci 6: 258-66.
//==================================================================
function make_Kv3_GP
if (({exists Kv3_GP}))
return
end
create tabchannel Kv3_GP
float npower = {npower_Kv3} // 4
setfield Kv3_GP Ek {EK} Gbar {G_Kv3_GP} Ik 0 Gk 0\
Xpower {npower} Ypower 1 Zpower 0
float Kn = {Kn_Kv3} // individual n-gate K
float Vhalfn = {Vhalfn_Kv3} // True Vhalf for channel activation.
float taunmax = 0.014 // actual peak of tauV curve is about 7 ms.
float taunmin = 0.0001 // = true min tau
float K1tau = -0.012
float K2tau = -0.013 // changed from -0.021 02/16/2005
float V0n, ninf, taun, alpha, beta
V0n = {Vhalfn} + ({Kn} * {log {(1 / {pow 0.5 {1/{npower}}}) - 1}})
echo "Kv3 V0n: " {V0n}
//V0n is Vhalf for each individual n gate.
call Kv3_GP TABCREATE X {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
ninf = 1 / (1 + {exp { ({V0n} - x) / {Kn} } } )
taun = {taunmin} + (({taunmax} - {taunmin}) / ({exp { ({V0n} - x) / {K1tau} } } + {exp {-({V0n} - x) / {K2tau} }}))
setfield Kv3_GP X_A->table[{i}] {taun}
setfield Kv3_GP X_B->table[{i}] {ninf}
/* Manual table contruction bypassing tweaktau:
alpha = {ninf} / {taun}
beta = {(1 / {taun}) - {alpha}}
setfield Kv3_GP X_A->table[{i}] {alpha}
setfield Kv3_GP X_B->table[{i}] {1 / {taun}}
*/
x = x + dx
end
tweaktau Kv3_GP X
call Kv3_GP TABFILL X {xdivs_interp} 0
setfield Kv3_GP X_A->calc_mode {NO_INTERP}
setfield Kv3_GP X_B->calc_mode {NO_INTERP}
float Kh = 0.010
float V0h = -0.02
float hmin = {hmin_Kv3} // 0.6
float tauhmax = 0.033
float tauhmin = 0.007
float tauhK = 0.010
float tauhV0 = 0 //-0.070
float hinf, tauh
call Kv3_GP TABCREATE Y {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
hinf = {hmin} + ((1 - {hmin}) / (1 + {exp {(x - {V0h}) / {Kh} }}))
tauh = {{tauhmax}-{tauhmin}} / (1 + {exp {(x - {tauhV0}) / {tauhK} }}) + {tauhmin}
setfield Kv3_GP Y_A->table[{i}] {tauh}
setfield Kv3_GP Y_B->table[{i}] {hinf}
x = x + dx
end
tweaktau Kv3_GP Y
call Kv3_GP TABFILL Y {xdivs_interp} 0
setfield Kv3_GP Y_A->calc_mode {NO_INTERP}
setfield Kv3_GP Y_B->calc_mode {NO_INTERP}
end
//==================================================================
// KA Kv4 fast
// Low voltage-activated
// Created based on GP data:
// Tkatch, Baranauskas and Surmeier
// 2000, J Neurosci 20(2):579-588
// Modified by J. R. Edgerton 02/2004
//==================================================================
function make_Kv4_fast_GP
if (({exists Kv4_fast_GP}))
return
end
create tabchannel Kv4_fast_GP
float npower = 4
setfield Kv4_fast_GP Ek {EK} Gbar {G_Kv4_fast_GP} Ik 0 Gk 0\
Xpower {npower} Ypower 1 Zpower 0
float Kn = {Kn_Kv4} // 0.029
float V0n = {V0n_Kv4} // -0.053
float taunmax = 0.007
float taunmin = 0.00025
float Ktaun1 = {Ktaun1_Kv4} // 0.029
float Ktaun2 = {Ktaun2_Kv4} // 0.029
float ninf, taun
// V0n = {Vhalfn} + ({Kn} * {log {(1 / {pow 0.5 {1/{npower}}}) - 1}})
echo "Kv4f V0n: " {V0n}
// V0n = -0.043 //corrected for mpower = 4.
call Kv4_fast_GP TABCREATE X {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
ninf = 1 / (1 + {exp {({V0n} - x) / {Kn} }})
taun = taunmin + ({taunmax} - {taunmin}) / ({exp {({V0n} - x) / {Ktaun1}}} + {exp {(x - {V0n}) / {Ktaun2}}})
setfield Kv4_fast_GP X_A->table[{i}] {taun}
setfield Kv4_fast_GP X_B->table[{i}] {ninf}
x = x + dx
end
tweaktau Kv4_fast_GP X
call Kv4_fast_GP TABFILL X {xdivs_interp} 0
setfield Kv4_fast_GP X_A->calc_mode {NO_INTERP}
setfield Kv4_fast_GP X_B->calc_mode {NO_INTERP}
float tauhmax = 0.021
float tauhmin = 0.007
float Kh = {Kh_Kv4} //-0.0047
float V0h = {V0h_Kv4} //-0.072
float Ktauh1 = {Ktauh1_Kv4} //0.010
float Ktauh2 = {Ktauh2_Kv4} //0.010
float hinf, tauh
call Kv4_fast_GP TABCREATE Y {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
hinf = 1 / (1 + {exp {({V0h} - x) / {Kh} }})
tauh = tauhmin + ({tauhmax} - {tauhmin}) / ({exp {({V0h} - x) / {Ktauh1}}} + {exp {(x - {V0h}) / {Ktauh2}}})
setfield Kv4_fast_GP Y_A->table[{i}] {tauh}
setfield Kv4_fast_GP Y_B->table[{i}] {hinf}
x = x + dx
end
tweaktau Kv4_fast_GP Y
call Kv4_fast_GP TABFILL Y {xdivs_interp} 0
setfield Kv4_fast_GP Y_A->calc_mode {NO_INTERP}
setfield Kv4_fast_GP Y_B->calc_mode {NO_INTERP}
end
//==================================================================
// KA Kv4 slow
// Low voltage-activated
// Created based on GP data:
// Tkatch, Baranauskas and Surmeier
// 2000, J Neurosci 20(2):579-588
// Modified by J. R. Edgerton 02/2004
//==================================================================
function make_Kv4_slow_GP
if (({exists Kv4_slow_GP}))
return
end
create tabchannel Kv4_slow_GP
float npower = 4
setfield Kv4_slow_GP Ek {EK} Gbar {G_Kv4_slow_GP} Ik 0 Gk 0\
Xpower {npower} Ypower 1 Zpower 0
float Kn = {Kn_Kv4} // 0.029
float V0n = {V0n_Kv4} // -0.053
float taunmax = 0.007
float taunmin = 0.00025
float Ktaun1 = {Ktaun1_Kv4} // 0.029
float Ktaun2 = {Ktaun2_Kv4} // 0.029
float ninf, taun
// V0n = {Vhalfn} + ({Kn} * {log {(1 / {pow 0.5 {1/{npower}}}) - 1}})
echo "Kv4s V0n: " {V0n}
// V0n = -0.043 //corrected for mpower = 4.
call Kv4_slow_GP TABCREATE X {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
ninf = 1 / (1 + {exp {({V0n} - x) / {Kn} }})
taun = taunmin + ({taunmax} - {taunmin}) / ({exp {({V0n} - x) / {Ktaun1}}} + {exp {(x - {V0n}) / {Ktaun2}}})
setfield Kv4_slow_GP X_A->table[{i}] {taun}
setfield Kv4_slow_GP X_B->table[{i}] {ninf}
x = x + dx
end
tweaktau Kv4_slow_GP X
call Kv4_slow_GP TABFILL X {xdivs_interp} 0
setfield Kv4_slow_GP X_A->calc_mode {NO_INTERP}
setfield Kv4_slow_GP X_B->calc_mode {NO_INTERP}
float tauhmax = 0.121
float tauhmin = 0.05
float Kh = {Kh_Kv4} //-0.0047
float V0h = {V0h_Kv4} //-0.072
float Ktauh1 = {Ktauh1_Kv4} //0.010
float Ktauh2 = {Ktauh2_Kv4} //0.010
float hinf, tauh
call Kv4_slow_GP TABCREATE Y {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
hinf = 1 / (1 + {exp {({V0h} - x) / {Kh} }})
tauh = tauhmin + ({tauhmax} - {tauhmin}) / ({exp {({V0h} - x) / {Ktauh1}}} + {exp {(x - {V0h}) / {Ktauh2}}})
setfield Kv4_slow_GP Y_A->table[{i}] {tauh}
setfield Kv4_slow_GP Y_B->table[{i}] {hinf}
x = x + dx
end
tweaktau Kv4_slow_GP Y
call Kv4_slow_GP TABFILL Y {xdivs_interp} 0
setfield Kv4_slow_GP Y_A->calc_mode {NO_INTERP}
setfield Kv4_slow_GP Y_B->calc_mode {NO_INTERP}
end
//==================================================================
// KCNQ
// Activation kinetics: Gamper, Stockand, Shapiro (2003). J Neurosci 23: 84-95.
// GV curve, deact kinetics: Prole & Marrion (2004). Biophys J. 86: 1454-69.
//==================================================================
function make_KCNQ_GP
if (({exists KCNQ_GP}))
return
end
create tabchannel KCNQ_GP
float npower = 4
setfield KCNQ_GP Ek {EK} Gbar {G_KCNQ_GP} Ik 0 Gk 0\
Xpower {npower} Ypower 0 Zpower 0
float taunmax = 0.1 //Q10 = 3 adjusted
float taunmin = 0.0067 //Q10 = 3 adjusted
float Kn = {Kn_KCNQ}
float Vhalfn = {Vhalfn_KCNQ} // True Vhalf for channel activation
float K1tau = -0.025
float K2tau = -0.035
float V0n, ninf, taun, alpha, beta
V0n = {Vhalfn} + ({Kn} * {log {(1 / {pow 0.5 {1/{npower}}}) - 1}})
echo "KCNQ V0n: " {V0n}
//V0n is Vhalf for each individual n gate.
call KCNQ_GP TABCREATE X {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
ninf = 1 / (1 + {exp { ({V0n} - x) / {Kn} } } )
taun = {taunmin} + (({taunmax} - {taunmin}) / ({exp { ({V0n} - x) / {K1tau} } } + {exp {-({V0n} - x) / {K2tau} }}))
setfield KCNQ_GP X_A->table[{i}] {taun}
setfield KCNQ_GP X_B->table[{i}] {ninf}
/* Manual table contruction bypassing tweaktau:
alpha = {ninf} / {taun}
beta = {(1 / {taun}) - {alpha}}
setfield KCNQ_GP X_A->table[{i}] {alpha}
setfield KCNQ_GP X_B->table[{i}] {1 / {taun}}
*/
x = x + dx
end
tweaktau KCNQ_GP X
call KCNQ_GP TABFILL X {xdivs_interp} 0
setfield KCNQ_GP X_A->calc_mode {NO_INTERP}
setfield KCNQ_GP X_B->calc_mode {NO_INTERP}
end
//==================================================================
// HVA Ca2+ Channels
// Voltage-dependent activation from GP data:
// Surmeier Seno and Kitai 1994
// J Neurophysio. 71(3):1272-1280
//==================================================================
//First make a calcium concentration object that will keep track of the
//Ca2+ coming in from the calcium channels and apply buffering.
function make_Ca_GP_conc
if (({exists Ca_GP_conc}))
return
end
create Ca_concen Ca_GP_conc
setfield Ca_GP_conc \
tau {tau_CaClearance} \ // sec
B 5.2e-6 \ // Moles per coulomb, later scaled to conc
Ca_base 5e-05 //Units in mM, so = 50 nM.
end
//Next make nernst object to keep track of Calcium reversal potential
//during changes in intracellular calcium concentration.
function make_Ca_GP_nernst
if (({exists Ca_GP_nernst}))
return
end
create nernst Ca_GP_nernst
setfield Ca_GP_nernst \
Cout 2 \ //external Ca2+ conc
Cin 5e-5 \ //baseline internal Ca2+ conc 50 nM
T 32 \ //temp in Celsius
valency 2 \ //divalent
scale 1 //E in volts
end
//Finally make actual calcium channels.
function make_Ca_HVA_GP
if (({exists Ca_HVA_GP}))
return
end
int ndivs, i
float x, y
create tabchannel Ca_HVA_GP
setfield Ca_HVA_GP Ek {ECa} Gbar {G_Ca_HVA_GP} Ik 0 Gk 0 \
Xpower {npower_CaHVA} Ypower 0 Zpower 0
//first setup voltage-dependent activation
float tau = 0.0002 //estimated from traces Q10=2.5 adjusted
float K = -1*{Kn_CaHVA} // -0.007
float V0 = {Vhalfn_CaHVA} // -0.002
setuptau Ca_HVA_GP X \
{tau} {tau*1e-6} 0 0 1e6 \
1 0 1 {-1.0*V0} {K} -range {xmin} {xmax}
call Ca_HVA_GP TABFILL X {xdivs_interp} 0
setfield Ca_HVA_GP X_A->calc_mode {NO_INTERP}
setfield Ca_HVA_GP X_B->calc_mode {NO_INTERP}
end
function make_Ca_HVA_GP2
if (({exists Ca_HVA_GP}))
return
end
int ndivs, i
float x, y
create tabchannel Ca_HVA_GP
setfield Ca_HVA_GP Ek {ECa} Gbar {G_Ca_HVA_GP} Ik 0 Gk 0 \
Xpower {npower_CaHVA} Ypower 0 Zpower 0
//first setup voltage-dependent activation
float Kn = {Kn_CaHVA}
float V0n = {Vhalfn_CaHVA} + ({Kn} * {log {(1 / {pow 0.5 {1/{npower_CaHVA}}}) - 1}})
float taunmin = 0.0002 //estimated from traces Q10=2.5 adjusted
float taunmax = 0.0002
for (i = 0; i <= {xdivs}; i = i + 1)
ninf = 1 / (1 + {exp { ({V0n} - x) / {Kn} } } )
taun = {taunmin} + (({taunmax} - {taunmin}) / ({exp { ({V0n} - x) / {Kn} } } + {exp {-({V0n} - x) / {Kn} }}))
setfield Ca_HVA_GP X_A->table[{i}] {taun}
setfield Ca_HVA_GP X_B->table[{i}] {ninf}
x = x + dx
end
tweaktau Ca_HVA_GP X
call Ca_HVA_GP TABFILL X {xdivs_interp} 0
setfield Ca_HVA_GP X_A->calc_mode {NO_INTERP}
setfield Ca_HVA_GP X_B->calc_mode {NO_INTERP}
end
//==================================================================
// SK channel from Volker Steuber's DCN neuron model, modified to
// reflect Hill fits in the following:
// Hirschberg et al, 1999: Biophys J. 77: 1905-13.
// Keen et al, 1999: J. Neurosci 19: 8830-38.
// Tau-Ca equation made by Volker based on Hirschberg et al, 1998:
// JGP 111: 565-581.
//==================================================================
function make_SK_GP
if ({exists K_ahp_GP})
return
end
float cxmin, cxmax, cxdivs, cdx
float taum, minf
float hillslope = 4.6 // Hirschberg et al, 1999
float taumax = 0.076 // deactivation tau in 0 Ca2+
float taumin = 0.004 // max activation rate
float caSat = 0.005 // calcium conc at which tauact hits max
float tauK = ({taumax} - {taumin}) / {caSat}
// NOTE: genesis SI concentration units = mols / m^3 = millimolar!
create tabchannel K_ahp_GP
setfield K_ahp_GP Ek {EK} Gbar {G_K_ahp_GP} \
Xpower 0 Ypower 0 Zpower 1
cxmin = 0.00001 // 10 nM
cxmax = 0.06 // 60 microM
// Conc-dependence grid will have xdivs_interp points spanning
// 1 nM to 6 microM with resolution of 1 nM.
cxdivs = 5999 // Have to use high-resolution for channel setup because
// most of G-Ca curve falls within the first 1 microM.
cdx = (cxmax - cxmin)/cxdivs
call K_ahp_GP TABCREATE Z {cxdivs} {cxmin} {cxmax}
x = cxmin
for (i = 0; i <= {cxdivs}; i = i + 1)
if (x < {caSat})
taum = ({taumax} - x*{tauK})/{dQ10_SK}
else
taum = {taumin}/{dQ10_SK}
end
minf = {pow {x} {hillslope}} / ({pow {x} {hillslope}} + {pow {EC50_SK} {hillslope}})
setfield K_ahp_GP Z_A->table[{i}] {taum}
setfield K_ahp_GP Z_B->table[{i}] {minf}
x = x + cdx
end
tweaktau K_ahp_GP Z
call K_ahp_GP TABFILL Z {xdivs_interp} 0
setfield K_ahp_GP Z_A->calc_mode {NO_INTERP}
setfield K_ahp_GP Z_B->calc_mode {NO_INTERP}
end
//==================================================================
// H current (Anomalous rectifier--mixed Na and K current)
// HCN1/HCN2 heteromeric channel, GP-specific
// Channel model from Chan et al (2004), J Neurosci 24: 9921-32.
// Original model from Siegelbaum lab. Wang et al (2002), Neuron 36:
// 451-62. Chen et al (2001), JGP 117: 491-504.
//==================================================================
function make_h_HCN_GP
if ({exists h_HCN_GP})
return
end
create tabchannel h_HCN_GP
setfield h_HCN_GP Ek {Eh} Gbar {{G_h_HCN_GP}} \
Xpower 1 Ypower 0 Zpower 0
float Km = -0.0033
float V0m = -0.0764
float taumin = 0
float tau0 = 14.5
float Ktau1 = 0.00748
float Ktau2 = 0.00656
float dq10 = 4
float minf, taum
call h_HCN_GP TABCREATE X {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
minf = 1 / (1 + {exp {({V0m} - x) / {Km} }})
taum = ({taumin} + {tau0} / ({exp {(x-{V0m})/{Ktau1}}} + {exp {({V0m}-x)/{Ktau2}}})) / dq10
setfield h_HCN_GP X_A->table[{i}] {taum}
setfield h_HCN_GP X_B->table[{i}] {minf}
x = x + dx
end
tweaktau h_HCN_GP X
call h_HCN_GP TABFILL X {xdivs_interp} 0
setfield h_HCN_GP X_A->calc_mode {NO_INTERP}
setfield h_HCN_GP X_B->calc_mode {NO_INTERP}
end
//==================================================================
// H current (Anomalous rectifier--mixed Na and K current)
// HCN2 homomeric channel, GP-specific
// Channel model from Chan et al (2004), J Neurosci 24: 9921-32.
// Original model from Siegelbaum lab. Wang et al (2002), Neuron 36:
// 451-62. Chen et al (2001), JGP 117: 491-504.
//==================================================================
function make_h_HCN2_GP
if ({exists h_HCN2_GP})
return
end
create tabchannel h_HCN2_GP
setfield h_HCN2_GP Ek {Eh} Gbar {{G_h_HCN2_GP}} \
Xpower 1 Ypower 0 Zpower 0
float Km = -0.004
float V0m = -0.0875
float taumin = 0
float tau0 = 25.2
float Ktau1 = 0.0082
float Ktau2 = 0.0089
float dq10 = 4
float minf, taum
call h_HCN2_GP TABCREATE X {xdivs} {xmin} {xmax}
x = xmin
for (i = 0; i <= {xdivs}; i = i + 1)
minf = 1 / (1 + {exp {({V0m} - x) / {Km} }})
taum = ({taumin} + {tau0} / ({exp {(x-{V0m})/{Ktau1}}} + {exp {({V0m}-x)/{Ktau2}}})) / dq10
setfield h_HCN2_GP X_A->table[{i}] {taum}
setfield h_HCN2_GP X_B->table[{i}] {minf}
x = x + dx
end
tweaktau h_HCN2_GP X
call h_HCN2_GP TABFILL X {xdivs_interp} 0
setfield h_HCN2_GP X_A->calc_mode {NO_INTERP}
setfield h_HCN2_GP X_B->calc_mode {NO_INTERP}
end