Disentangling astroglial physiology with a realistic cell model in silico (Savtchenko et al 2018)

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Accession:243508
"Electrically non-excitable astroglia take up neurotransmitters, buffer extracellular K+ and generate Ca2+ signals that release molecular regulators of neural circuitry. The underlying machinery remains enigmatic, mainly because the sponge-like astrocyte morphology has been difficult to access experimentally or explore theoretically. Here, we systematically incorporate multi-scale, tri-dimensional astroglial architecture into a realistic multi-compartmental cell model, which we constrain by empirical tests and integrate into the NEURON computational biophysical environment. This approach is implemented as a flexible astrocyte-model builder ASTRO. As a proof-of-concept, we explore an in silico astrocyte to evaluate basic cell physiology features inaccessible experimentally. ..."
Reference:
1 . Savtchenko LP, Bard L, Jensen TP, Reynolds JP, Kraev I, Medvedev N, Stewart MG, Henneberger C, Rusakov DA (2018) Disentangling astroglial physiology with a realistic cell model in silico. Nat Commun 9:3554 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Glia;
Brain Region(s)/Organism: Hippocampus;
Cell Type(s): Astrocyte;
Channel(s): I Calcium; I Potassium; Kir;
Gap Junctions: Gap junctions;
Receptor(s):
Gene(s):
Transmitter(s): Glutamate;
Simulation Environment: NEURON; MATLAB; C or C++ program;
Model Concept(s): Calcium waves; Calcium dynamics; Potassium buffering; Volume transmission; Membrane Properties;
Implementer(s): Savtchenko, Leonid P [leonid.savtchenko at ucl.ac.uk];
Search NeuronDB for information about:  I Calcium; I Potassium; Kir; Glutamate;
: calcium flux gap junction. 2018
: 04 01 2018
: Modification of ica

NEURON {
    POINT_PROCESS GapCa
    NONSPECIFIC_CURRENT icagap
    USEION ca READ cai WRITE ica
    RANGE TimeRelex, icagap, ica, BasicCa, fluxion, jd, ControlGap
    POINTER gapCaP
}

UNITS {
    (molar) =	(1/liter)
    (mM) =	(millimolar)
    (um) =	(micron)
    (mA) =	(milliamp)
    FARADAY =	(faraday)	(10000 coulomb)
    PI = (pi)	(1)
}

PARAMETER {
    TimeRelex = 10000 (ms) 
    BasicCa = 1 (mM)
	jd = 0 (mA/mM)
	ControlGap = 0
	
}

ASSIGNED {
    cai (mM)
    gapCaP (mM)
    diam (um)
    icagap (nanoamp)
    fluxion (mM ms)
    ica  (nanoamp) : so you can plot the calcium current generated by this mechanism
}

BREAKPOINT {
    fluxion=BasicCa*TimeRelex 
	if (ControlGap < 0.5) {ica = jd * (1e+6)*(cai - 50e-6 (mM))
		 }  else {
			ica = jd * (1e+6)*(cai - gapCaP)
		 }
	
    : ica = (1e+16)*(((cai - 50e-6 (mM))/fluxion)*(2*FARADAY))            : Gap junction between Astrocytes
	
    : ica = jd * (1e+6)*(cai - gapCaP)         : Gap Junction inside the astrocyte   
}

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