Calcium waves and mGluR-dependent synaptic plasticity in CA1 pyr. neurons (Ashhad & Narayanan 2013)

 Download zip file   Auto-launch 
Help downloading and running models
Accession:150551
A morphologically realistic, conductance-based model equipped with kinetic schemes that govern several calcium signalling modules and pathways in CA1 pyramidal neurons
Reference:
1 . Ashhad S, Narayanan R (2013) Quantitative interactions between the A-type K+ current and inositol trisphosphate receptors regulate intraneuronal Ca2+ waves and synaptic plasticity. J Physiol 591:1645-69 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell; Synapse; Channel/Receptor; Dendrite;
Brain Region(s)/Organism: Hippocampus;
Cell Type(s): Hippocampus CA1 pyramidal GLU cell;
Channel(s): I Na,t; I L high threshold; I T low threshold; I A; I K; Ca pump;
Gap Junctions:
Receptor(s): AMPA; NMDA; mGluR; IP3;
Gene(s):
Transmitter(s): Glutamate;
Simulation Environment: NEURON;
Model Concept(s): Active Dendrites; Synaptic Plasticity; Signaling pathways; Calcium dynamics; G-protein coupled; Calcium waves;
Implementer(s): Narayanan, Rishikesh [rishi at iisc.ac.in]; Ashhad, Sufyan [soofy at mbu.iisc.ernet.in];
Search NeuronDB for information about:  Hippocampus CA1 pyramidal GLU cell; AMPA; NMDA; mGluR; IP3; I Na,t; I L high threshold; I T low threshold; I A; I K; Ca pump; Glutamate;
/
AshhadNarayanan2013
Readme.html
cal4.mod
Calamp.mod
caltype.mod
camax.mod
cat.mod
ghknmda.mod
ip3dif.mod
kadist.mod *
kaprox.mod *
kdrca1.mod
mglur.mod
na3.mod
nax.mod *
Wghkampa.mod
CalciumWave.hoc
distance.hoc
Fig4F-G.hoc
Fig6C-F.hoc
mosinit.hoc
n123.hoc
n123_all.dis
n123_all.rdis
ObliquePath.hoc
oblique-paths.hoc
parameters.hoc
screenshot4F.png
screenshot4G.png
screenshot6C-F.png
                            
COMMENT
Two state kinetic scheme synapse described by rise time taur,
and decay time constant taud. The normalized peak condunductance is 1.
Decay time MUST be greater than rise time.

The solution of A->G->bath with rate constants 1/taur and 1/taud is
 A = a*exp(-t/taur) and
 G = a*taud/(taud-taur)*(-exp(-t/taur) + exp(-t/taud))
	where taur < taud

If taud-taur -> 0 then we have a alphasynapse.
and if taur -> 0 then we have just single exponential decay.

The factor is evaluated in the
initial block such that an event of weight 1 generates a
peak conductance of 1.

Because the solution is a sum of exponentials, the
coupled equations can be solved as a pair of independent equations
by the more efficient cnexp method.

ENDCOMMENT

NEURON {
	POINT_PROCESS ghknmda
	USEION na WRITE ina
	USEION k WRITE ik
	USEION ca READ cai, cao WRITE ica
	
	RANGE taur, taud
	RANGE inmda

	RANGE P, mg, Pmax :AreaFactor
	GLOBAL  mgb
}

UNITS {
	(nA) = (nanoamp)
	(mV) = (millivolt)
	(uS) = (microsiemens)
	(molar) = (1/liter)
	(mM) = (millimolar)
	FARADAY = (faraday) (coulomb)
	R = (k-mole) (joule/degC)
  	(um)    = (micron)
  	PI      = (pi)       (1)

}

PARAMETER {
	taur=5 (ms) <1e-9,1e9>
	taud = 50 (ms) <1e-9,1e9>
	cai = 100e-6(mM)	: 100nM
	cao = 2		(mM)
	nai = 18	(mM)	: Set for a reversal pot of +55mV
	nao = 140	(mM)
	ki = 140	(mM)	: Set for a reversal pot of -90mV
	ko = 5		(mM)
	celsius		(degC)
	mg = 2		(mM)
	Pmax=1e-6   (cm/s)	: According to Canavier, PNMDA's default value is
						: 1e-6 for 10uM, 1.4e-6 cm/s for 30uM of NMDA
	:AreaFactor =250 (cm2) : Computed from PI*Diam*1e2
}

ASSIGNED {
	ina     (mA/cm2)
	ik      (mA/cm2)
	ica     (mA/cm2)
	v (mV)
	P (cm/s)
	factor
	mgb	(1)
	inmda	(mA/cm2)

	diam (um)
}

STATE {
	A (cm/s)
	B (cm/s)
}

INITIAL {
	LOCAL tp
	if (taur/taud > .9999) {
		taur = .9999*taud
	}
	A = 0
	B = 0
	tp = (taur*taud)/(taud - taur) * log(taud/taur)
	factor = -exp(-tp/taur) + exp(-tp/taud)
	factor = 1/factor
}

BREAKPOINT {
	SOLVE state METHOD cnexp
	P=B-A
	mgb = mgblock(v)

: Area is for unit conversion from nA to mA/cm2 which is what ica, ina and ik use.
 
	ina = P*mgb*ghk(v, nai, nao,1)     :/AreaFactor	
	ica = P*10.6*mgb*ghk(v, cai, cao,2)  :/AreaFactor
	ik = P*mgb*ghk(v, ki, ko,1)      :/AreaFactor
	inmda = ica + ik + ina
}

DERIVATIVE state {
	A' = -A/taur
	B' = -B/taud
}

FUNCTION ghk(v(mV), ci(mM), co(mM),z) (0.001 coul/cm3) {
	LOCAL arg, eci, eco
	arg = (0.001)*z*FARADAY*v/(R*(celsius+273.15))
	eco = co*efun(arg)
	eci = ci*efun(-arg)
	ghk = (0.001)*z*FARADAY*(eci - eco)
}

FUNCTION efun(z) {
	if (fabs(z) < 1e-4) {
		efun = 1 - z/2
	}else{
		efun = z/(exp(z) - 1)
	}
}

FUNCTION mgblock(v(mV)) (1){
	TABLE 
	DEPEND mg
	FROM -140 TO 80 WITH 1000 

	: from Jahr & Stevens, JNS, 1990

	mgblock = 1 / (1 + exp(0.062 (/mV) * -v) * (mg / 3.57 (mM)))
}

NET_RECEIVE(weight (uS)) { 	: No use to weight, can be used instead of Pmax,
							: if you want NetCon access to the synaptic
							: conductance.
	state_discontinuity(A, A + Pmax*factor)
	state_discontinuity(B, B + Pmax*factor)
}

Loading data, please wait...