/******************************************************************************************************
***ref: Biophysical Properties and Slow Voltage-dependent Inactivation of a
Sustained Sodium Current in Entorhinal Cortex Layer-II Principal Neurons
A Whole-Cell and Single-Channel Study. Magistretti,et.al. 1999
kai.du@ki.se
**********************************************************************************************************/
function make_NaP_channel
float Erev = 0.05 // V
str path = "NaP_channel"
float xmin = -0.10 /* minimum voltage we will see in the simulation */ // V
float xmax = 0.05 /* maximum voltage we will see in the simulation */ // V
int xdivsFiner = 3000
int c = 0
/****** Begin vars used to enable genesis calculations ********/
float increment = (xmax - xmin)*1e3/xdivsFiner // mV
echo "NaP: increment" {increment} "mV"
float x = -100.00 // mV
float minf = 0
float hinf = 0
float mvhalf = -52.6 // mV, Magistretti,et.al. 1999
float mshift = 0.0 // mV
float mslope = 4.6 // mV,
float hvhalf = -48.8 // mV, Magistretti,et.al. 1999
float hslope = 10.0 //
float hshift = 0.0 // mV
float taum = 0 // ms
float tauh = 0 // ms
/****** End vars used to enable genesis calculations **********/
create tabchannel {path}
call {path} TABCREATE X {xdivsFiner} {xmin} {xmax} // activation gate
call {path} TABCREATE Y {xdivsFiner} {xmin} {xmax} // inactivation gate
// set tau_m table
float qfactor = 3.0 // 1.0,
create table NaP_tauh // ms
call NaP_tauh TABCREATE 15 {xmin} {xmax}
create table NaP_taum // ms
call NaP_taum TABCREATE 3000 {xmin} {xmax}
//the table corresponds to -100 mV to 50 mV
setfield NaP_tauh table->table[0] 4500 \
table->table[1] 4750 \
table->table[2] 5200 \
table->table[3] 6100 \
table->table[4] 6300 \
table->table[5] 5000 \
table->table[6] 4250 \
table->table[7] 3500 \
table->table[8] 3000 \
table->table[9] 2700 \
table->table[10] 2500 \
table->table[11] 2100 \
table->table[12] 2100 \
table->table[13] 2100 \
table->table[14] 2100 \
table->table[15] 2100
call NaP_tauh TABFILL {xdivsFiner} 2
for(c = 0; c < {xdivsFiner} + 1; c = c + 1)
minf = 1/(1 + {exp {-(x - mvhalf + mshift)/mslope}})
hinf = 1/(1 + {exp {(x - hvhalf + hshift)/hslope}})
// taum was taken from Traub,et.al. 2003
// the same as in Wolf, et.al. 2005's model, which has been corrected for qfactor
if ({x<-40})
taum = 0.025 + 0.14* {exp {( (x + 40 )/10)}}
else
taum = 0.02 + 0.145* {exp {( (-x - 40)/10)}}
end
tauh = {getfield NaP_tauh table->table[{c}]}/qfactor
setfield {path} X_A->table[{c}] {taum*1e-3}
setfield {path} X_B->table[{c}] {minf}
setfield {path} Y_A->table[{c}] {tauh*1e-3}
setfield {path} Y_B->table[{c}] {hinf}
x = x + increment
end
/* Defines the powers of m Hodgkin-Huxley equation*/
setfield {path} Ek {Erev} Xpower 1 Ypower 1
/* fill the tables with the values of tau and minf/hinf
* calculated from tau and minf/hinf
*/
tweaktau {path} X
tweaktau {path} Y
// write channel tables to the files
tab2file ./MScell/tables/NaPXtable.txt {path} X_A -table2 X_B -overwrite
tab2file ./MScell/tables/NaPYtable.txt {path} Y_A -table2 Y_B -overwrite
end
| 
