Dentate granule cell: mAHP & sAHP; SK & Kv7/M channels (Mateos-Aparicio et al., 2014)

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The model is based on that of Aradi & Holmes (1999; Journal of Computational Neuroscience 6, 215-235). It was used to help understand the contribution of M and SK channels to the medium afterhyperpolarization (mAHP) following one or seven spikes, as well as the contribution of M channels to the slow afterhyperpolarization (sAHP). We found that SK channels are the main determinants of the mAHP, in contrast to CA1 pyramidal cells where the mAHP is primarily caused by the opening of M channels. The model reproduced these experimental results, but we were unable to reproduce the effects of the M-channel blocker XE991 on the sAHP. It is suggested that either the XE991-sensitive component of the sAHP is not due to M channels, or that when contributing to the sAHP, these channels operate in a mode different from that associated with the mAHP.
1 . Mateos-Aparicio P, Murphy R, Storm JF (2014) Complementary functions of SK and Kv7/M potassium channels in excitability control and synaptic integration in rat hippocampal dentate granule cells. J Physiol 592:669-93 [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; Dendrite;
Brain Region(s)/Organism:
Cell Type(s): Dentate gyrus granule GLU cell;
Channel(s): I Na,t; I L high threshold; I N; I T low threshold; I A; I K; I M; I K,Ca; I Sodium; I Calcium; I Potassium;
Gap Junctions:
Simulation Environment: NEURON;
Model Concept(s): Ion Channel Kinetics; Detailed Neuronal Models; Action Potentials; Calcium dynamics; Spike Frequency Adaptation; Conductance distributions;
Implementer(s): Murphy, Ricardo [ricardo.murphy at];
Search NeuronDB for information about:  Dentate gyrus granule GLU cell; I Na,t; I L high threshold; I N; I T low threshold; I A; I K; I M; I K,Ca; I Sodium; I Calcium; I Potassium;
/////////////// Setup, stimulus and run /////////// //

proc Initialize() {

proc doStop() {
  stoprun = 1

objref stim, hold, git, gvit
proc run() {
  stoprun = 0

	forall {Ra = Ra0  cm = cm0}
	forall nseg = int((L/(0.1*lambda_f(100))+0.9)/2)*2 + 1

	objref stim, hold
	access soma
	hold = new holdingi(0.5)
	hold.ic = 0.001*ihold      			//nA

	savedt = dt
	tstop = 1e10
	dt = 0.1*tstop
	continuerun(tstop)              //Initial steady state
  dt = savedt

	stim = new IClamp(0.5)
	stim.del = dur1
	stim.dur = dur2
	stim.amp = 0.001*amplitude      //nA
	tstop = dur1 + dur2 + dur3

	git = new Graph(0)
  git.view(0, 0, tstop, 0.002*amplitude, 0, 450, 370, 155)
	git.label(0,0.8, "I(nA)")

	gvit = new Graph(0)
  gvit.view(0, -80, tstop, 120, 0, 150, 370, 155)
	gvit.label(0,0.8, "V(mV)")

xpanel("DGC model parameters")
xvalue("Initialization V(mV)", "v_init",1)
xvalue("Holding current (pA)", "ihold",1)
xvalue("Test-pulse I    (pA)", "amplitude",1)
xvalue("Duraion 1       (ms)", "dur1",1)
xvalue("Duraion 2       (ms)", "dur2",1)
xvalue("Duraion 3       (ms)", "dur3",1)
xpvalue("t", &t)
xvalue("Cm         (uF/um^2)", "cm0", 1)
xvalue("Rm       (kOhm-cm^2)", "Rm0", 1,"gpas = 1/(Rm0*1e3)")
xvalue("Ra          (Ohm-cm)", "Ra0", 1)
xvalue("EK              (mV)", "EK", 1)
xvalue("gMaxon     (pS/um^2)", "gMaxon", 1)
xvalue("1/slope         (mV)", "kKM", 1)
xvalue("M Vshift        (mV)", "VshiftKM", 1)
xvalue("V0-EK           (mV)", "v0erevKM", 1)
xvalue("kVM             (mV)", "kVM", 1)
xvalue("gamma               ", "gammaKM", 1)
xvalue("tauM = tauM/        ", "taudivKM", 1)
xvalue("DtauM1 = DtauM1*    ", "Dtaumult1", 1)
xvalue("DtauM2 = DtauM2*    ", "Dtaumult2", 1)
xvalue("tau0M = tau0M*      ", "tau0mult", 1)
xvalue("gKDR multipier      ", "KDRmult", 1)
xvalue("V0KDR           (mV)", "V0KDR", 1)
xvalue("tauKDR = tauKDR*    ", "taumultKDR", 1)
xvalue("gsksoma     (S/cm^2)", "gsksoma", 1)
xvalue("gskprox     (S/cm^2)", "gskprox", 1)
xvalue("gskGCLs     (S/cm^2)", "gskGCLs", 1)
xvalue("ESK             (mV)", "erevSK", 1)
xvalue("tausk = tausk/      ", "tauskdiv", 1)
xvalue("BK multipier        ", "BKmult", 1)
xvalue("EBK             (mV)", "erevBK", 1)
xvalue("CaT multipier       ", "CaTmult", 1)
xvalue("CaN multipier       ", "CaNmult", 1)
xvalue("CaL multipier       ", "CaLmult", 1)
xvalue("CaT V shift     (mV)", "Vshift", 1)
xvalue("tauCaT = tauCaT/    ", "tauctdiv", 1)
xvalue("gNaT_mult           ", "gNaT_mult", 1)
xvalue("ENa             (mV)", "ENa", 1)
xvalue("mtauNa = mtauNa*    ", "taumultNa", 1)
xvalue("htauNa = htauNa*    ", "htaumultNa", 1)
xvalue("gA_axon     (S/cm^2)", "gKAa", 1)
xvalue("gA_soma     (S/cm^2)", "gKAs", 1)
xvalue("tauCa = tauCa/      ", "taucadiv", 1)
xvalue("[Ca2+]i(0)      (mM)", "ca0", 1)
xvalue("gbar_sAHP   (S/cm^2)", "gbarsAHP", 1)
xvalue("tau1Ref_sAHP    (ms)", "tau1RefsAHP", 1)
xvalue("tau2_sAHP       (ms)", "tau2sAHP", 1)
xvalue("c1inf_sAHP          ", "c1infsAHP", 1)
xvalue("oinf_sAHP           ", "oinfsAHP", 1)
xvalue("CaRef_sAHP      (mM)", "CaRefsAHP", 1)
xvalue("[Ca2+]half      (mM)", "cahsAHP", 1)
xvalue("k[Ca2+]         (mM)", "kcasAHP", 1)
xvalue("n for IsAHP    (O^n)", "nsAHP", 1)
xvalue("gbarUK     (pS/um^2)", "gbarUK", 1)
xvalue("EUK             (mV)", "erevUK", 1)
xvalue("VhalfUK         (mV)", "VhalfUK", 1)
xvalue("kUK             (mV)", "kUK", 1)
xvalue("pUK                 ", "pUK", 1)
xvalue("tauUK           (ms)", "tauUK", 1)
xvalue("kCaUK           (mM)", "kcaUK", 1)