Intrinsic sensory neurons of the gut (Chambers et al. 2014)

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Accession:155796
A conductance base model of intrinsic neurons neurons in the gastrointestinal tract. The model contains all the major voltage-gated and calcium-gated currents observed in these neurons. This model can reproduce physiological observations such as the response to multiple brief depolarizing currents, prolonged depolarizing currents and hyperpolarizing currents. This model can be used to predict how different currents influence the excitability of intrinsic sensory neurons in the gut.
Reference:
1 . Chambers JD, Bornstein JC, Gwynne RM, Koussoulas K, Thomas EA (2014) A detailed, conductance-based computer model of intrinsic sensory neurons of the gastrointestinal tract. Am J Physiol Gastrointest Liver Physiol 307:G517-32 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell; Channel/Receptor;
Brain Region(s)/Organism:
Cell Type(s): Gastrointestinal tract intrinsic sensory neuron;
Channel(s): I Na,p; I Na,t; I K,leak; I K,Ca; I CAN; I Mixed; I Na, leak; Ca pump;
Gap Junctions:
Receptor(s):
Gene(s): Nav1.3 SCN3A; Nav1.7 SCN9A; Nav1.9 SCN11A SCN12A;
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Detailed Neuronal Models; Action Potentials; Calcium dynamics;
Implementer(s): Chambers, Jordan [jordandchambers at gmail.com];
Search NeuronDB for information about:  I Na,p; I Na,t; I K,leak; I K,Ca; I CAN; I Mixed; I Na, leak; Ca pump;
TITLE nav17.mod  
 
COMMENT
EAT 14Sep09 Kinetic model based on the Sheets NaV1.7 model
            that also allows binding to inactivated states.
ENDCOMMENT
 
UNITS {
    (mA) =(milliamp)
    (mV) =(millivolt)
    (uF) = (microfarad)
    (molar) = (1/liter)
    (nA) = (nanoamp)
    (mM) = (millimolar)
    (um) = (micron)
}

? interface 
NEURON { 
    SUFFIX nav17 
    USEION na READ ena WRITE ina VALENCE 1
    RANGE gna
    RANGE gnabar
    RANGE ina, jina17
    RANGE alphaD, betaD
}

INDEPENDENT {t FROM 0 TO 100 WITH 100 (ms)}

PARAMETER {
    v (mV) 
    dt (ms) 
    ena  (mV)
    gnabar = 1e-1 (mho/cm2)
    alphaD = 0.05 (/ms)
    betaD = 0.02 (/ms)
    mam = 5 (mV)
    mah = 122.35 (mV)
    mas = 93.9 (mV)
    sam = -12.08 (mV)
    sah = 15.29 (mV)
    sas = 16.6 (mV)
    mbm = 72.7 (mV)
    sbm = 16.7 (mV)
    jina17 (mA/cm2)
}

STATE {
    O C1 C2 C3 I I1 I2 I3 I10S I11S I12S I13S I20S I21S I22S I23S ID ID1 ID2 ID3
}

KINETIC scheme1 {
    rates(v)
 
    ~ O    <-> C1   (3*bm,   am)
    ~ O    <-> I    (  bh,   ah)
    ~ O    <-> I10S (  bs,   as)
    ~ C1   <-> C2   (2*bm, 2*am)
    ~ C1   <-> I1   (  bh,   ah)
    ~ C1   <-> I11S (  bs,   as)
    ~ C2   <-> C3   (  bm, 3*am)
    ~ C2   <-> I2   (  bh,   ah)
    ~ C2   <-> I12S (  bs,   as)
    ~ C3   <-> I3   (  bh,   ah)
    ~ C3   <-> I13S (  bs,   as)
    ~ I    <-> I1   (3*bm,   am)
    ~ I    <-> I20S (  bs,   as)
    ~ I    <-> ID   (  bd,   ad)
    ~ I1   <-> I2   (2*bm, 2*am)
    ~ I1   <-> ID1  (  bd,   ad)
    ~ I1   <-> I21S (  bs,   as)
    ~ I2   <-> I3   (  bm, 3*am)
    ~ I2   <-> ID2  (  bd,   ad)
    ~ I2   <-> I22S (  bs,   as)
    ~ I3   <-> ID3  (  bd,   ad)
    ~ ID   <-> ID1  (3*bm,   am)
    ~ ID1  <-> ID2  (2*bm, 2*am)
    ~ ID2  <-> ID3  (  bm, 3*am)
    ~ I10S <-> I20S (  bh,   ah)
    ~ I11S <-> I21S (  bh,   ah)
    ~ I12S <-> I22S (  bh,   ah)
    ~ I13S <-> I23S (  bh,   ah)
    
    CONSERVE O+C1+C2+C3+I+I1+I2+I3+I10S+I11S+I12S+I13S+I20S+I21S+I22S+I23S+ID+ID1+ID2+ID3 = 1
}

ASSIGNED {
    gna (mho/cm2) 
    ina (mA/cm2)
    am (/ms)
    bm (/ms)
    ah (/ms)
    bh (/ms)
    as (/ms)
    bs (/ms)
    ad (/ms)
    bd (/ms)
    htau (ms)
    hinf
} 

? currents
BREAKPOINT {
    SOLVE scheme1 METHOD sparse
    gna = gnabar*O  
    ina = gna*(v - ena)
    jina17 = ina
}

UNITSOFF

INITIAL {
    rates(v)
    SOLVE scheme1 STEADYSTATE sparse
}

? rates
PROCEDURE rates(v) {
    : NaV1.7 from Sheets et al
    am =15.5/(1+exp((v-mam)/(sam)))
    bm = 35.2/(1+exp((v+mbm)/sbm))
    
    ah = 0.38685/(1+exp((v+mah)/sah))
    bh = -.00283+2.00283/(1+exp((v+5.5266)/(-12.70195)))
    
    as = .00003+(.00092)/(1+exp((v+mas)/sas))
    bs = 132.05-(132.05)/(1+exp((v-384.9)/28.5))
    
    ad = alphaD
    bd = betaD
}

UNITSON

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