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

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Accession:169240
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.
Reference:
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]
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 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:
Receptor(s):
Gene(s):
Transmitter(s):
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 medisin.uio.no];
Search NeuronDB for information about:  Dentate gyrus granule 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;
/*//////////////////// Biophysics ////////////////////

Channel mechanisms:

  pas = passive leak conductance
   KM = M conductance                  (DGC_M.mod)
   KA = A-type conductance             (Aradi_KA.mod)
 fKDR = fast delayed rectifier         (Aradi_KDRf.mod)
 sKDR = fast delayed rectifier         (Aradi_KDRs.mod)
CaDep = SK and BK channels             (Aradi_CadepK.mod)
 sAHP = slow AHP conductance           (DGC_sAHP.mod)
   Na = transient Na conductance       (Aradi_Na.mod)
   Ca = T, N and L -type Ca channels   (Aradi_Ca.mod)
   UK = ad-hoc unknown conductance     (DGC_UK.mod)

"g...bar" indicates a specific conductance while
"mult" and "div" indicate multipliers and divisors. See
the .mod files and the panel in "SetUp.hoc" for units.

/*////////////////////////////////////////////////////


proc InsertChannels() {

	forsec all {
    insert pas
      g_pas = gpas
      e_pas = Epas
  }

  forsec dendrites {
    cm = 1.6*cm0
    insert pas
      g_pas = 4e-05
      e_pas = Epas
  }

  forsec GCLs {
    insert Ca
      gtcabar_Ca = CaTmult*0.0003
      gncabar_Ca = CaNmult*0.003
      glcabar_Ca = CaLmult*0.015
    insert CadepK
      gbkbar_CadepK = BKmult*0.0003
      gskbar_CadepK = gskGCLs
    insert Na
      gbar_Na = gNaT_mult*0.018
    insert fKDR
      gbar_fKDR = 0.004
    insert sKDR
      gbar_sKDR = 0.003
  }

  forsec proxs {
    insert Ca
      gtcabar_Ca = CaTmult*0.001
      gncabar_Ca = CaNmult*0.001
      glcabar_Ca = CaLmult*0.015
    insert CadepK
      gbkbar_CadepK = BKmult*0.0005
      gskbar_CadepK = gskprox
    insert Na
      gbar_Na = gNaT_mult*0.013
    insert fKDR
      gbar_fKDR = 0.004
    insert sKDR
      gbar_sKDR = 0.003
  }

  forsec middles {
    insert Ca
      gtcabar_Ca = CaTmult*0.002
      gncabar_Ca = CaNmult*0.001
      glcabar_Ca = CaLmult*0.001
    insert CadepK
      gbkbar_CadepK = BKmult*0.0012
      gskbar_CadepK = 0.0
    insert Na
      gbar_Na = gNaT_mult*0.008
    insert fKDR
      gbar_fKDR = 0.001
    insert sKDR
      gbar_sKDR = 0.003
  }

  forsec distals {
    insert Ca
      gtcabar_Ca = CaTmult*0.002
      gncabar_Ca = CaNmult*0.001
      glcabar_Ca = 0.0
    insert CadepK
      gbkbar_CadepK = BKmult*0.0012
      gskbar_CadepK = 0.0
    insert fKDR
      gbar_fKDR = 0.001
    insert sKDR
      gbar_sKDR = 0.004
  }

  forsec allaxon {
    insert Na
      gbar_Na = gNaT_mult*0.21	//0.04  (S-H)
    insert fKDR
      gbar_fKDR = 0.028
    insert KA
			gbar_KA = gKAa	//0.004
    insert KM
    	k_KM = kKM
    	v0erev_KM = v0erevKM
    	kV_KM = kVM
    	gamma_KM = gammaKM
    	taudiv_KM = taudivKM
    	Dtaumult1_KM = Dtaumult1
    	Dtaumult2_KM = Dtaumult2
    	Vshift_KM = VshiftKM
			tau0mult_KM = tau0mult
			gbar_KM = gMaxon
  }

  soma {
    insert Ca
      gtcabar_Ca = CaTmult*0.00015
      gncabar_Ca = CaNmult*0.002
      glcabar_Ca = CaLmult*0.01
    insert CadepK
      gbkbar_CadepK = BKmult*0.0003
      gskbar_CadepK = gsksoma
    insert Na
      gbar_Na = gNaT_mult*0.12
    insert fKDR
      gbar_fKDR = 0.016
    insert sKDR
      gbar_sKDR = 0.003
    insert KA
    	gbar_KA = gKAs
    insert UK
    	gbar_UK = gbarUK
    insert sAHP
    	gbar_sAHP = gbarsAHP
  }

  forsec all {
		if (ismembrane("Na")) {
			ena = ENa
			taumult_Na = taumultNa
		}
		if (ismembrane("UK")) {
			erev_UK = erevUK
			p_UK = pUK
			tau_UK = tauUK
			Vhalf_UK = VhalfUK
			k_UK = kUK
			taucadiv_UK = taucadiv
			kca_UK = kcaUK
			ca0_UK = ca0
		}
		if (ismembrane("Ca")) {
			taucadiv_Ca = taucadiv
			tauctdiv_Ca = tauctdiv
			Vshift_Ca = Vshift
			ca0_Ca = ca0
		}
		if (ismembrane("CadepK")) { ek = EK
			erevSK_CadepK = erevSK
			tauskdiv_CadepK = tauskdiv
			taucadiv_CadepK = taucadiv
			erevBK_CadepK = erevBK
			ca0_CadepK = ca0
		}
		if (ismembrane("KM")) {erev_KM = EK}
		if (ismembrane("KA")) {erev_KA = EK}
		if (ismembrane("fKDR")) {
			erev_fKDR = EK
			gbar_fKDR = KDRmult*gbar_fKDR
			v0_fKDR = V0KDR
			taumult_fKDR = taumultKDR
		}
		if (ismembrane("sKDR")) {
			erev_sKDR = EK
			gbar_sKDR = KDRmult*gbar_sKDR
		}
		if (ismembrane("sAHP")) {
			ek = EK
			tau1Ref_sAHP = tau1RefsAHP
			tau2_sAHP = tau2sAHP
			c1inf_sAHP = c1infsAHP
			oinf_sAHP = oinfsAHP
			CaRef_sAHP = CaRefsAHP
			kca_sAHP = kcasAHP
			cah_sAHP = cahsAHP
			n_sAHP = nsAHP
		}
	}
}


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