A dynamic corral model of receptor trafficking at a synapse
The postsynaptic density (PSD) is a cytoskeletal
specialization within the postsynaptic membrane of a neuron that
helps to concentrate and organize neurotransmitter receptors at a
chemical synapse. The total number of receptors within the PSD,
which is a major factor in determining the physiological strength or
weight of a synapse, fluctuates due to the surface diffusion of
receptors into and out of the PSD, and the interactions of receptors
with scaffolding proteins and cytoskeletal elements within the
PSD. In this paper we present a stochastic model of protein receptor
trafficking at the PSD that takes into account these various
processes. The PSD is treated as a stochastically-gated corral,
which contributes a source of extrinsic or environmental noise that
supplements the intrinsic noise arising from small receptor
numbers. Using a combination of stochastic analysis and Monte Carlo
simulations, we determine the time-dependent variation in the mean
and variance of synaptic receptor numbers for a variety of initial
conditions that simulate fluorescence recovery after photobleaching
experiments, and indicate how such data might be used to infer
certain properties of the PSD.
University of Utah
| Department of Mathematics
|
bressloff@math.utah.edu
Jan 2004.