A mathematical model of evoked calcium dynamics in astrocytes (Handy et al 2017)

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Accession:189344
" ...Here we present a qualitative analysis of a recent mathematical model of astrocyte calcium responses. We show how the major response types are generated in the model as a result of the underlying bifurcation structure. By varying key channel parameters, mimicking blockers used by experimentalists, we manipulate this underlying bifurcation structure and predict how the distributions of responses can change. We find that store-operated calcium channels, plasma membrane bound channels with little activity during calcium transients, have a surprisingly strong effect, underscoring the importance of considering these channels in both experiments and mathematical settings. ..."
Reference:
1 . Handy G, Taheri M, White JA, Borisyuk A (2017) Mathematical investigation of IP3-dependent calcium dynamics in astrocytes. J Comput Neurosci 42:257-273 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Glia;
Brain Region(s)/Organism:
Cell Type(s):
Channel(s): Ca pump; I_SERCA; I Calcium;
Gap Junctions:
Receptor(s): IP3;
Gene(s):
Transmitter(s):
Simulation Environment: MATLAB; XPP;
Model Concept(s): Calcium dynamics; Oscillations; Bifurcation;
Implementer(s): Handy, Gregory [handy at math.utah.edu]; Taheri, Marsa ;
Search NeuronDB for information about:  IP3; I Calcium; I_SERCA; Ca pump;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Copyright: Marsa Taheri and Gregory Handy, 2016
% This code was used to simulate the mathematical model of Astrocyte 
% IP3-dependent Ca responses in 2 papers submitted in Nov 2016.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Default parameters for calcium channels and IP3 transient
% Global variables are accessed by Paper_Ca_ODE_TH file
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  
clear;

global gamma delta v_ip3r v_leak v_in k_out v_pmca k_pmca
global d1 d2 d3 d5 a2
global v_serca k_serca
global k_soc v_soc
global stim_time d_rise d_decay
global r_rise Amp

%% Pump/Receptor/Leak Parameters
gamma=5.4054;
 
% Leak for ER
v_leak=0.002; 

% Leak for Extracellular Space
v_in=0.05; 
k_out=1.2;

% IP3R Parameters
v_ip3r=0.222;
% Li-Rinzel Parameters
d1=0.13; d2=1.049; d3=943.4e-3; d5=0.08234; 
a2=0.04; %adjusted Li-Rinzel Parameter

% PMCA Terms
v_pmca=10; k_pmca=2.5;

% SOCC Terms
v_soc=1.57;k_soc=90;

% SERCA Terms
v_serca=0.9;k_serca=0.1;
 
% Sneyd Parameter
delta=0.2;

%% IP3 Parameters (reproduces a SP response) 
stim_time=20;
Amp=0.375; 
d_rise=17;
d_decay=97; 
r_rise=0.002; 

 

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