Paper Info
Title
Barriers To Diffusion In Dendrites And Estimation Of Calcium Spread Following Synaptic Inputs
Abstract
The motion of ions, molecules or proteins in dendrites is restricted by cytoplasmic obstacles such as organelles, microtubules and actin network. To account for molecular crowding, we study the effect of diffusion barriers on local calcium spread in a dendrite. We first present a model based on a dimension reduction approach to approximate a three dimensional diffusion in a cylindrical dendrite by a one-dimensional effective diffusion process. By comparing uncaging experiments of an inert dye in a spiny dendrite and in a thin glass tube, we quantify the change in diffusion constants due to molecular crowding as D-cyto/D-water = 1/20. We validate our approach by reconstructing the uncaging experiments using Brownian simulations in a realistic 3D model dendrite. Finally, we construct a reduced reaction-diffusion equation to model calcium spread in a dendrite under the presence of additional buffers, pumps and synaptic input. We find that for moderate crowding, calcium dynamics is mainly regulated by the buffer concentration, but not by the cytoplasmic crowding, dendritic spines or synaptic inputs. Following high frequency stimulations, we predict that calcium spread in dendrites is limited to small microdomains of the order of a few microns (<5 mu m).
Year
DOI
Venue
2011
10.1371/journal.pcbi.1002182
PLOS COMPUTATIONAL BIOLOGY
Keywords
Field
DocType
diffusion process,dendritic spine,three dimensional,reaction diffusion equation,dimension reduction
Diffusion process,Anatomy,Synapse,Dendritic spine,Calcium,Biology,Biophysics,Cytoplasm,Genetics,Brownian motion,Calcium signaling,Dendrite
Journal
Volume
Issue
ISSN
7
10
1553-734X
Citations 
PageRank 
References 
3
0.71
2
Authors
3
Name
Order
Citations
PageRank
Armin Biess191.22
Eduard Korkotian261.99
David Holcman37614.22