Amyloid beta (IA block) effects on a model CA1 pyramidal cell (Morse et al. 2010)

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Accession:87284
The model simulations provide evidence oblique dendrites in CA1 pyramidal neurons are susceptible to hyper-excitability by amyloid beta block of the transient K+ channel, IA. See paper for details.
Reference:
1 . Morse TM, Carnevale NT, Mutalik PG, Migliore M, Shepherd GM (2010) Abnormal excitability of oblique dendrites implicated in early Alzheimer's: a computational study Front. Neural Circuits 4:16 [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:
Cell Type(s): Hippocampus CA1 pyramidal cell;
Channel(s): I Na,t; I L high threshold; I N; I T low threshold; I A; I K; I h; I K,Ca;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Dendritic Action Potentials; Active Dendrites; Detailed Neuronal Models; Pathophysiology; Aging/Alzheimer`s;
Implementer(s): Carnevale, Ted [Ted.Carnevale at Yale.edu]; Morse, Tom [Tom.Morse at Yale.edu];
Search NeuronDB for information about:  Hippocampus CA1 pyramidal cell; I Na,t; I L high threshold; I N; I T low threshold; I A; I K; I h; I K,Ca;
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CA1_abeta
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readme.html
cacumm.mod
cagk.mod *
cal2.mod *
can2.mod *
cat.mod *
distr.mod *
h.mod
ipulse2.mod *
kadist.mod
kaprox.mod
kdrca1.mod
na3n.mod
naxn.mod *
zcaquant.mod
aBeta.hoc
add_ca.hoc
bAP_peak_vecs.hoc
c91662.ses
C91662_Link.txt
cond_report.hoc
control_boxes.hoc
distribute_currents.hoc
fig1.jpg
fig2.jpg
fig2A_c91662.hoc
fig3.jpg
fig3.ses
fig4.jpg
fig4.ses
fig5.jpg
fig6b.jpg
figs.hoc
find_averages.hoc
fixnseg.hoc
GaspiriniEtAl2007Fig1Stimulation.ses
generate_conc_graph.hoc
gka_averager.hoc
graph_na3_kinetics.hoc
init_and_run_and_graph.hoc
leaky_distal.hoc
maxica.hoc
maxica.ses.20100525
mosinit.hoc
na3_shifter.hoc
ntc_additions.hoc
oblique_application.hoc
oblique_scaled_ka.hoc
obliques_primary_tuft.hoc
paper_fig_buttons.hoc
sectiontest.hoc
shrink_obliques.hoc
SubBranch.hoc
trigger_and_start.hoc
wait_for_go.hoc
                            
TITLE CaGk
: Calcium activated K channel.
: Modified from Moczydlowski and Latorre (1983) J. Gen. Physiol. 82

UNITS {
	(molar) = (1/liter)
}

UNITS {
	(mV) =	(millivolt)
	(mA) =	(milliamp)
	(mM) =	(millimolar)
}


NEURON {
	SUFFIX cagk
	USEION ca READ cai
	USEION k READ ek WRITE ik
	RANGE gbar,gkca,ik
	GLOBAL oinf, tau
}

UNITS {
	FARADAY = (faraday)  (kilocoulombs)
	R = 8.313424 (joule/degC)
}

PARAMETER {
	celsius		(degC)
	v		(mV)
	gbar=.01	(mho/cm2)	: Maximum Permeability
	cai 		(mM)
	ek		(mV)

	d1 = .84
	d2 = 1.
	k1 = .48e-3	(mM)
	k2 = .13e-6	(mM)
	abar = .28	(/ms)
	bbar = .48	(/ms)
        st=1            (1)
}

ASSIGNED {
	ik		(mA/cm2)
	oinf
	tau		(ms)
        gkca          (mho/cm2)
}

INITIAL {
        rate(v,cai)
        o=oinf
}

STATE {	o }		: fraction of open channels

BREAKPOINT {
	SOLVE state METHOD cnexp
	gkca = gbar*o^st
	ik = gkca*(v - ek)
}

DERIVATIVE state {	: exact when v held constant; integrates over dt step
	rate(v, cai)
	o' = (oinf - o)/tau
}

FUNCTION alp(v (mV), c (mM)) (1/ms) { :callable from hoc
	alp = c*abar/(c + exp1(k1,d1,v))
}

FUNCTION bet(v (mV), c (mM)) (1/ms) { :callable from hoc
	bet = bbar/(1 + c/exp1(k2,d2,v))
}

FUNCTION exp1(k (mM), d, v (mV)) (mM) { :callable from hoc
	exp1 = k*exp(-2*d*FARADAY*v/R/(273.15 + celsius))
}

PROCEDURE rate(v (mV), c (mM)) { :callable from hoc
	LOCAL a
	a = alp(v,c)
	tau = 1/(a + bet(v, c))
	oinf = a*tau
}


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