Cerebellar purkinje cell: K and Ca channels regulate APs (Miyasho et al 2001)

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Accession:17664
We adopted De Schutter and Bower's model as the starting point, then modified the descriptions of several ion channels, such as the P-type Ca channel and the delayed rectifier K channel, and added class-E Ca channels and D-type K channels to the model. Our new model reproduces most of our experimental results and supports the conclusions of our experimental study that class-E Ca channels and D-type K channels are present and functioning in the dendrites of Purkinje neurons.
Reference:
1 . Miyasho T, Takagi H, Suzuki H, Watanabe S, Inoue M, Kudo Y, Miyakawa H (2001) Low-threshold potassium channels and a low-threshold calcium channel regulate Ca2+ spike firing in the dendrites of cerebellar Purkinje neurons: a modeling study. Brain Res 891:106-15 [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): Cerebellum Purkinje GABA cell;
Channel(s): I Na,p; I Na,t; I T low threshold; I A; I K; I M; I K,Ca; I Sodium; I Calcium; I Potassium; I A, slow; I_KD;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Action Potential Initiation; Activity Patterns; Dendritic Action Potentials; Bursting; Active Dendrites; Influence of Dendritic Geometry; Detailed Neuronal Models; Action Potentials; Calcium dynamics;
Implementer(s): Miyakawa, H [Miyakawa at ls.toyaku.ac.jp];
Search NeuronDB for information about:  Cerebellum Purkinje GABA cell; I Na,p; I Na,t; I T low threshold; I A; I K; I M; I K,Ca; I Sodium; I Calcium; I Potassium; I A, slow; I_KD;
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prknj
readme
CaE.mod *
CalciumP.mod *
CaP.mod *
CaP2.mod *
CaT.mod *
K2.mod *
K22.mod *
K23.mod *
KA.mod *
KC.mod *
KC2.mod *
KC3.mod *
KD.mod *
Kdr.mod *
Kh.mod *
Khh.mod *
KM.mod *
Leak.mod *
NaF.mod *
NaP.mod *
mosinit.hoc
purkinje.hoc
purkinje.ses
                            
TITLE BK calcium-activated potassium current
: Calcium activated K channel.
COMMENT
  from "An Active Membrane Model of the Cerebellar Purkinje Cell
        1. Simulation of Current Clamp in Slice"
ENDCOMMENT

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

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


INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}

NEURON {
	SUFFIX KC3
	USEION ca READ cai
	USEION k WRITE ik
	RANGE gkbar,gk,zinf,ik
}


PARAMETER {
	celsius=37	(degC)
	v		(mV)
	gkbar=.08	(mho/cm2)	: Maximum Permeability
	cai = .04e-3	(mM)
	ek  = -85	(mV)
	dt		(ms)
}


ASSIGNED {
	ik		(mA/cm2)
	minf
	mexp
	zinf
	zexp
	gk
}

STATE {	m z }		: fraction of open channels

BREAKPOINT {
	SOLVE state
:	gk = gkbar*m*z*z
	ik = gkbar*m*z*z*(v - ek)
}
:UNITSOFF
:LOCAL fac

:if state_cagk is called from hoc, garbage or segmentation violation will
:result because range variables won't have correct pointer.  This is because
: only BREAKPOINT sets up the correct pointers to range variables.
PROCEDURE state() {	: exact when v held constant; integrates over dt step
	rate(v, cai)
	m = m + mexp*(minf - m)
	z = z + zexp*(zinf - z)
	VERBATIM
	return 0;
	ENDVERBATIM
}

INITIAL {
	rate(v, cai)
	m = minf
	z = zinf
}

FUNCTION alp(v (mV), ca (mM)) (1/ms) { :callable from hoc
	alp = 400/(ca*1000)
}

FUNCTION bet(v (mV)) (1/ms) { :callable from hoc
	bet = 0.11/exp((v-35)/14.9)
}

PROCEDURE rate(v (mV), ca (mM)) { :callable from hoc
	LOCAL a,b
	a = alp(v,ca)
	zinf = 1/(1+a)
	zexp = (1 - exp(-dt/10))
	b = bet(v)
	minf = 7.5/(7.5+b)
	mexp = (1 - exp(-dt*(7.5+b)))
}
:UNITSON

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