CA1 pyramidal neuron: functional significance of axonal Kv7 channels (Shah et al. 2008)

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Accession:112546
The model used in this paper confirmed the experimental findings suggesting that axonal Kv7 channels are critically and uniquely required for determining the inherent spontaneous firing of hippocampal CA1 pyramids, independently of alterations in synaptic activity. The model predicts that the axonal Kv7 density could be 3-5 times that at the soma.
Reference:
1 . Shah MM, Migliore M, Valencia I, Cooper EC, Brown DA (2008) Functional significance of axonal Kv7 channels in hippocampal pyramidal neurons. Proc Natl Acad Sci U S A 105:7869-74 [PubMed]
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Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell; Axon; Channel/Receptor;
Brain Region(s)/Organism:
Cell Type(s): Hippocampus CA1 pyramidal cell;
Channel(s): I Na,t; I T low threshold; I A; I K; I M; I Calcium;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Action Potential Initiation; Detailed Neuronal Models; Axonal Action Potentials; Action Potentials;
Implementer(s): Migliore, Michele [Michele.Migliore at Yale.edu];
Search NeuronDB for information about:  Hippocampus CA1 pyramidal cell; I Na,t; I T low threshold; I A; I K; I M; I Calcium;
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readme.html
cacumm.mod *
cagk.mod
cal2.mod
can2.mod
cat.mod *
h.mod *
kadist.mod *
KahpM95.mod *
kaprox.mod *
kdrca1.mod *
km.mod *
na3n.mod *
naxn.mod *
fig4a.hoc
fixnseg.hoc *
geo9068802.hoc *
mosinit.hoc *
screenshot.jpg
                            
TITLE I-h channel from Magee 1998 for distal dendrites

UNITS {
	(mA) = (milliamp)
	(mV) = (millivolt)

}

PARAMETER {
	v 		(mV)
        ehd  		(mV)        
	celsius 	(degC)
	ghdbar=.0001 	(mho/cm2)
        vhalfl=-73   	(mV)
	kl=-8
        vhalft=-75   	(mV)
        a0t=0.011      	(/ms)
        zetat=2.2    	(1)
        gmt=.4   	(1)
	q10=4.5
	qtl=1
}


NEURON {
	SUFFIX hd
	NONSPECIFIC_CURRENT i
        RANGE ghdbar, vhalfl
        GLOBAL linf,taul
}

STATE {
        l
}

ASSIGNED {
	i (mA/cm2)
        linf      
        taul
        ghd
}

INITIAL {
	rate(v)
	l=linf
}


BREAKPOINT {
	SOLVE states METHOD cnexp
	ghd = ghdbar*l
	i = ghd*(v-ehd)

}


FUNCTION alpt(v(mV)) {
  alpt = exp(0.0378*zetat*(v-vhalft)) 
}

FUNCTION bett(v(mV)) {
  bett = exp(0.0378*zetat*gmt*(v-vhalft)) 
}

DERIVATIVE states {     : exact when v held constant; integrates over dt step
        rate(v)
        l' =  (linf - l)/taul
}

PROCEDURE rate(v (mV)) { :callable from hoc
        LOCAL a,qt
        qt=q10^((celsius-33)/10)
        a = alpt(v)
        linf = 1/(1 + exp(-(v-vhalfl)/kl))
:       linf = 1/(1+ alpl(v))
        taul = bett(v)/(qtl*qt*a0t*(1+a))
}