Effects of KIR current inactivation in NAc Medium Spiny Neurons (Steephen and Manchanda 2009)

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Accession:121060
"Inward rectifying potassium (KIR) currents in medium spiny (MS) neurons of nucleus accumbens inactivate significantly in ~40% of the neurons but not in the rest, which may lead to differences in input processing by these two groups. Using a 189-compartment computational model of the MS neuron, we investigate the influence of this property using injected current as well as spatiotemporally distributed synaptic inputs. Our study demonstrates that KIR current inactivation facilitates depolarization, firing frequency and firing onset in these neurons. ..."
Reference:
1 . Steephen JE, Manchanda R (2009) Differences in biophysical properties of nucleus accumbens medium spiny neurons emerging from inactivation of inward rectifying potassium currents. J Comput Neurosci 27:453-70 [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;
Brain Region(s)/Organism: Basal ganglia;
Cell Type(s): Nucleus accumbens spiny projection neuron;
Channel(s): I Na,p; I L high threshold; I T low threshold; I p,q; I A; I h; I K,Ca; I CAN; I A, slow; I Krp; I R;
Gap Junctions:
Receptor(s): AMPA; NMDA; Gaba;
Gene(s): Cav1.3 CACNA1D; Cav1.2 CACNA1C; IRK;
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Action Potential Initiation; Ion Channel Kinetics; Action Potentials; Synaptic Integration; Delay;
Implementer(s): Steephen, John Eric [johneric at iitb.ac.in];
Search NeuronDB for information about:  AMPA; NMDA; Gaba; I Na,p; I L high threshold; I T low threshold; I p,q; I A; I h; I K,Ca; I CAN; I A, slow; I Krp; I R;
TITLE Fast Sodium current 
: Unit check passed

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

UNITS { 
	(mV) = (millivolt) 
	(mA) = (milliamp) 
} 
NEURON { 
	SUFFIX NaF
	USEION na READ ena WRITE ina
	RANGE g, gmax, ina
	GLOBAL minf, mtau, hinf, htau
}
PARAMETER { : PARAMETERS ARE BY DEFAULT GLOBAL VARIABLES
	gmax = 0.0195 	(mho/cm2)
	ena (mV)
	m_vh = -23.9	(mV)	: half activation 
	m_ve = -11.8	(mV)	: slope
	h_vh = -62.9	(mV) : half activation
	h_ve = 10.7	(mV) : slope
} 
ASSIGNED { 
	v 		(mV)
	g		(mho/cm2)
	ina 		(mA/cm2) 
	minf 		(1)
	mtau 	(ms)
	hinf 		(1)
	htau 		(ms) 
} 
STATE {
	m h
}
BREAKPOINT { 
	SOLVE states METHOD cnexp
	g = gmax * m*m*m * h
	ina = g * (v - ena ) 
} 
INITIAL { 
	rates(v) 
	m = minf
	h = hinf
} 
DERIVATIVE states { 
	rates(v)
	m' = ( minf - m ) / mtau 
	h' = ( hinf - h ) / htau
}
FUNCTION_TABLE tabmtau(v(mV)) (ms) 
FUNCTION_TABLE tabhtau(v(mV)) (ms) 

PROCEDURE rates(v(mV)) { 
	TABLE mtau, htau, minf, hinf DEPEND h_vh FROM -120 TO 40 WITH 160
:	TABLE mtau, htau, minf, hinf DEPEND h_vh FROM -120 TO 40 WITH 320
	mtau = tabmtau(v)
	htau = tabhtau(v)
	minf = 1/(1 + exp((v - m_vh)/m_ve))
	hinf = 1/(1 + exp((v - h_vh)/h_ve))
}