I have written the following mod file describing a GABA synapse with DSI (depolarization-induced suppression of inhibition) according to the equations of page 544 in Zachriou et al 2014 https://pubmed.ncbi.nlm.nih.gov/25123173/. I am in the process of correcting/debugging/compiling this mod file. I have defined two pointers, vpre and post as my code requires access to the presynaptic and postsynaptic voltage.

In running nrnivmodl I get the error:

*Use of POINTER is not thread-safe. And non-Ascii character in line 42:ICAG_50 =0.000002 (mΜ) :Half-inhibition concentration (WIN).*

I am not sure what these two errors mean/refer to.

thank you for any help/guidance with this,

Alexandra

Code: Select all

```
TITLE model of GABAa receptors with endocanabinoid release
COMMENT
-----------------------------------------------------------------------------
Author: Alexandra Chatzikalymniou
Reference: Zachariou et al 2013,
-----------------------------------------------------------------------------
ENDCOMMENT
INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}
NEURON {
POINT_PROCESS GABAa_endocan
POINTER vpre, vpost
RANGE kA_minus, IGABA_A, gA_inf, kA_plus, h_AG_AG_bar, qA_inf, AG_bar
NONSPECIFIC_CURRENT i
GLOBAL kappa_plus, BAG_max, ICAG_50, nh, tau_qA, kd_max, gA_bar, VA, tau_GA, MGL
}
UNITS {
(nA) = (nanoamp)
(mV) = (millivolt)
(umho) = (micromho)
(mS) = (millisiemens)
(mM) = (millimolar)
}
PARAMETER {
kappa_plus =0.3 (1/ms) :Maximal reluctant-to-willing transition rate
BAG_max =0.5 :Maximum inhibition (due to AG)
nh =1.2 :Hill coefficient
tau_qA =1000 (ms) :CB1 recending time constant
kd_max =100 (mV) :Scaling factor
gA_bar =0.3 (mS/cm2) :GABA peak conductance
VA =-80 (mV) : GABA reversal potential
tauA =1 (ms) :GABA synaptic time constant
MGL =0.64 :monoacylglycerol lipase (MGL) controls the duration of DSE, DSI duration is determined by both MGL and COX-2.
ICAG_50 =0.000002 (mΜ) :Half-inhibition concentration (WIN)
}
ASSIGNED {
kappa_minus (ms) :Maximal reluctant-to-willing transition rate
gA_inf (mS/cm2) :inf conductance
kA_plus (ms) : willing to reluctant transition rate
h_AG(AG_bar) (ms) :
qA_inf (ms) : maximum fraction of bound G proteins
AG_bar (ms) :fraction of AG mobilised by the post-synaptic cell
gA (mS/cm2) :conductance
wA (mS/cm2) :The fraction of willing pre-synaptic Ca2+ channels
qA (1/ms) :fraction of bound G proteins
AG (1/ms) :AG mobilised by the post-synaptic cell
}
BREAKPOINT {
SOLVE release
kA_minus = kA_minus/(1+exp(-(vpre/5)))
IGABA_A = gA_bar*gA*(vpost - VA)
gA_inf(vpre, wA)= 1/(1+exp(-(vpre-kd_max*(1-wA))/5))
kA_plus = kappa_plus*qA
h_AG(AG_bar) = BAG_max/(1+(ICAG_50/AG_bar)^nh)
qA_inf = h_AG(AG_bar)
AG_bar = (1-MGL)*AG
}
DERIVATIVE scheme1 {
gA'=((gA_inf(vpre, wA))-gA)/tauA
}
DERIVATIVE scheme2 {
wA'=kA_minus*(1-wA)-kA_plus*wA
}
DERIVATIVE scheme3 {
qA'=(qA_inf-qA)/tau_qA
}
```