I apologise in advance if my question is being posted in wrong place. My problem concerns a transient potassium current which is extremely low-voltage activated, and I created the MOD file based on my experimental data. So when I want to insert this mechanism into my reconstructed cell, it unfortunately works as a leak conductance (I assume, because of the huge window current), so is there any way, I overlooked or misinterpreted something in my code? It would be greeat if this could be solved without changing the activation or inactivation Boltzmann equations, due to the fact, that these are measured currents, and my experiments show, that the presence or absence of this current doesn't change the input resistance.

Here's my current:

Code: Select all

```
TITLE KA TOR
: K-A current for hippocampal interneurons from Lien et al (2002)
NEURON {
SUFFIX katd
USEION k READ ek WRITE ik
RANGE gbar
GLOBAL minf, hinf, acthalf, actsteep, acttauavg, acttauoffset, acttauwdt, inactsteep, inactoffset, acttaupeak, inacttaupeak, inacttauxoffset, inacttauwdt, inacttauyoffset
}
PARAMETER {
gbar = 0.0002 (mho/cm2)
celsius
ek (mV) : must be explicitly def. in hoc
v (mV)
q10=3
acthalf = 67
actsteep = 25
acttauavg = 0.1
acttauoffset = 57.5
acttauwdt
acttaupeak = 10
inactsteep = 15
inactoffset = 68
inacttaupeak = 45
inacttauxoffset = 57.5
inacttauwdt = 30
inacttauyoffset = 9
}
UNITS {
(mA) = (milliamp)
(mV) = (millivolt)
(pS) = (picosiemens)
(um) = (micron)
}
ASSIGNED {
ik (mA/cm2)
minf mtau (ms)
hinf htau (ms)
}
STATE { m1 h1 h2}
BREAKPOINT {
SOLVE states METHOD cnexp
ik = gbar*m1*h1*(v - ek)
}
INITIAL {
trates(v)
m1=minf
h1=hinf
}
DERIVATIVE states {
trates(v)
m1' = (minf-m1)/mtau
h1' = (hinf-h1)/htau
}
PROCEDURE trates(v) {
LOCAL qt
qt=q10^((celsius-23)/10)
:Costum functions for better fitting
acttauwdt = 9.53952+(0.79058-9.53952)/(1+exp((v+47.97192)/3.35462))
minf = (1/(1 + exp(-(v+acthalf)/actsteep)))^4
mtau=acttauavg+acttaupeak*exp(-0.5*((v+acttauoffset)/acttauwdt)^2)
hinf = 1/(1 + exp((v+inactoffset)/inactsteep))
htau = inacttauyoffset+inacttaupeak*exp(-0.5*((v+inacttauxoffset)/inacttauwdt)^2)
}
```

Kind regards,

Viktor