Regulation of motoneuron excitability by KCNQ/Kv7 modulators (Lombardo & Harrington 2016)

 Download zip file   Auto-launch 
Help downloading and running models
Accession:217882
" ... Computer simulations confirmed that pharmacological enhancement of KCNQ/Kv7 channel (M current) activity decreases excitability and also suggested that the effects of inhibition of KCNQ/Kv7 channels on the excitability of spinal MNs do not depend on a direct effect in these neurons but likely on spinal cord synaptic partners. These results indicate that KCNQ/Kv7 channels have a fundamental role in the modulation of the excitability of spinal MNs acting both in these neurons and in their local presynaptic partners. ..."
Reference:
1 . Lombardo J, Harrington MA (2016) Non-reciprocal mechanisms of up- and down-regulation of spinal motoneuron excitability by modulators of KCNQ/Kv7 channels. J Neurophysiol :jn.00446.2016 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell;
Brain Region(s)/Organism: Spinal motoneuron;
Cell Type(s): Spinal cord motor neuron;
Channel(s): I Potassium; I K; I Na,t; I M;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Axonal Action Potentials;
Implementer(s): Lombardo, Joseph [josslomb at gmail.com];
Search NeuronDB for information about:  Spinal cord motor neuron; I Na,t; I K; I M; I Potassium;
/
LombardoHarrington2016
readme.html
Gfluctdv.mod *
ghchan.mod *
kca2.mod *
kdrRL.mod *
Km.mod *
kv1_gp.mod
L_Ca.mod *
mAHP.mod *
na3n.mod
na3rp.mod *
naps.mod *
napsi.mod *
buttons.png
ctrl.png
FR3cablepas.hoc
FRMot3dendNaHH.hoc
gKm0.png
GraphicsKmModulators.hoc
ModifiedFRMotoneuron.hoc
mosinit.hoc
retigabine.png
standard_0.hoc
Tools.ses
XE991.png
                            
COMMENT
km.mod
Potassium channel, Hodgkin-Huxley style kinetics
Based on I-M (muscarinic K channel)
Slow, noninactivating
Author: Zach Mainen, Salk Institute, 1995, zach@salk.edu
	
ENDCOMMENT

INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}

NEURON {
	SUFFIX Km
	USEION k READ ek WRITE ik
	RANGE n, gk, gbar
	RANGE ninf, ntau
	GLOBAL Ra, Rb
	GLOBAL q10, temp, tadj, vmin, vmax
}

UNITS {
	(mA) = (milliamp)
	(mV) = (millivolt)
	(pS) = (picosiemens)
	(um) = (micron)
} 

PARAMETER {
	v 		(mV)
	dt		(ms)
	gbar = 10   	(pS/um2)	: 0.03 mho/cm2
	tha  = -30	(mV)		: v 1/2 for inf
	qa   = 9	(mV)		: inf slope		
	Ra   = 0.001	(/ms)		: max act rate  (slow)
	Rb   = 0.001	(/ms)		: max deact rate  (slow)
	celsius		(degC)
	temp = 23	(degC)		: original temp 	
	q10  = 2.3			: temperature sensitivity
	vmin = -120	(mV)
	vmax = 100	(mV)
} 


ASSIGNED {
	a		(/ms)
	b		(/ms)
	ik 		(mA/cm2)
	gk		(pS/um2)
	ek		(mV)
	ninf
	ntau (ms)	
	tadj
}
 

STATE { n }

INITIAL { 
	trates(v)
	n = ninf
}

BREAKPOINT {
        SOLVE states
	gk = tadj*gbar*n
	ik = (1e-4) * gk * (v - ek)
} 

LOCAL nexp

PROCEDURE states() {   : Computes state variable n 
        trates(v)      : at the current v and dt.
        n = n + nexp*(ninf-n)
        VERBATIM
        return 0;
        ENDVERBATIM
}

PROCEDURE trates(v) {  :Computes rate and other constants at current v.
                       :Call once from HOC to initialize inf at resting v.
        LOCAL tinc
        TABLE ninf, nexp
	DEPEND dt, celsius, temp, Ra, Rb, tha, qa
	
	FROM vmin TO vmax WITH 199

	rates(v): not consistently executed from here if usetable_hh == 1
        tadj = q10^((celsius - temp)/10)  :temperature adjastment
        tinc = -dt * tadj
        nexp = 1 - exp(tinc/ntau)
}


PROCEDURE rates(v) {  :Computes rate and other constants at current v.
                      :Call once from HOC to initialize inf at resting v.

        a = Ra * (v - tha) / (1 - exp(-(v - tha)/qa))
        b = -Rb * (v - tha) / (1 - exp((v - tha)/qa))
        ntau = 1/(a+b)
	ninf = a*ntau
}

Loading data, please wait...