The optimal height of the synaptic cleft
- 6 February 2007
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 104 (6), 1823-1828
- https://doi.org/10.1073/pnas.0606636104
Abstract
Signal integration in the brain is determined by the size and kinetics of rapid synaptic responses. The latter, in turn, depends on the concentration profile of neurotransmitter in the synaptic cleft. According to a traditional view, narrower clefts should correspond to higher intracleft concentrations of neurotransmitter, and therefore to the enhanced activation of synaptic receptors. Here, we argue that narrowing the cleft also increases electrical resistance of the intracleft medium and therefore reduces local receptor currents. We employ detailed theoretical analyses and Monte Carlo simulations to propose that these two contrasting phenomena result in a relatively narrow range of cleft heights at which the synaptic receptor current reaches its maximum. Over a physiological range of synaptic parameters, the "optimum" height falls between approximately 12 and 20 nm. This range is consistent with the structure of central synapses reported by electron microscopy. Therefore, our results suggest that a simple fundamental principle may underlie the synaptic cleft architecture: to maximize synaptic strength.This publication has 60 references indexed in Scilit:
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