Endocannabinoid dynamics gate spike-timing dependent depression and potentiation (Cui et al 2016)

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Accession:187605
The endocannabinoid (eCB) system is considered involved in synaptic depression. Recent reports have also linked eCBs to synaptic potentiation. However it is not known how eCB signaling may support such bidirectionality. To question the mechanisms of this phenomena in spike-timing dependent plasticity (STDP) at corticostriatal synapses, we combined electrophysiology experiments with biophysical modeling. We demonstrate that STDP is controlled by eCB levels and dynamics: prolonged and moderate levels of eCB lead to eCB-mediated long-term depression (eCB-tLTD) while short and large eCB transients produce eCB-mediated long-term potentiation (eCB-tLTP). Therefore, just like neurotransmitters glutamate or GABA, eCB form a bidirectional system.
Reference:
1 . Cui Y, Prokin I, Xu H, Delord B, Genet S, Venance L, Berry H (2016) Endocannabinoid dynamics gate spike-timing dependent depression and potentiation. Elife 5:e13185 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Synapse; Channel/Receptor;
Brain Region(s)/Organism:
Cell Type(s): Neostriatum medium spiny direct pathway GABA cell; Neostriatum medium spiny indirect pathway GABA cell; Neostriatum spiny neuron;
Channel(s): I L high threshold; I Calcium; I_SERCA; I Cl, leak; Ca pump;
Gap Junctions:
Receptor(s): AMPA; NMDA; mGluR; Glutamate; IP3;
Gene(s):
Transmitter(s):
Simulation Environment: FORTRAN; Python;
Model Concept(s): Ion Channel Kinetics; Coincidence Detection; Parameter Fitting; Synaptic Plasticity; Long-term Synaptic Plasticity; Signaling pathways; STDP; Calcium dynamics; Parameter sensitivity; G-protein coupled; Neuromodulation;
Implementer(s):
Search NeuronDB for information about:  Neostriatum medium spiny direct pathway GABA cell; Neostriatum medium spiny indirect pathway GABA cell; AMPA; NMDA; mGluR; Glutamate; IP3; I L high threshold; I Calcium; I_SERCA; I Cl, leak; Ca pump;
!    -*- f95 -*-
! (c) 2016 - Ilya Prokin - isprokin@gmail.com - https://sites.google.com/site/ilyaprokin
! INRIA Rhone-Alpes
! STDP model : GHK flux
module ghk_flux
    implicit none
    contains

    real*8 function efun(x)
        implicit none
        real*8 :: x
        if (abs(x)<1e-4) then
            efun = 1-x/2
        elseif (x<=85) then
            efun = x/(exp(x)-1)
        else
            efun = 0
        endif
    end function efun

    real*8 function ghk(v, ci, co, pars)
        use pars_mod, only : pars_type
        implicit none
        real*8 :: v, ci, co
        type(pars_type) :: pars
        real*8 :: x, eco, eci
        ! (v(mV), ci(mM), co(mM)) (.001 coul/cm3)
        x = pars%common%zS*pars%common%F*v*1e-3/pars%common%RT
        ! 1e-3 mV to V
        eco = co*efun(x)
        eci = ci*efun(-x)
        ! high cao charge moves inward
        ! negative potential charge moves inward
        ghk = pars%common%zS*pars%common%F*(eci - eco)
    end function ghk

end module ghk_flux

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