A study on efficiency of 3D partial differential diffusive model of presynaptic processes

摘要

The verification of efficiency of the diffusive-type model of neurotransmitter transport dynamics inside the presynaptic bouton, including the spatial aspect of the transport, is the main objective of the simulations described in this paper. Finite element and finite difference methods were applied to solve the model numerically. The bouton was represented by a 3D tetrahedral mesh. Some biological parameters have been taken from scientific literature whereas some other remain unknown. Therefore the simulations were performed for various values of the unknown parameters. Such an approach allowed us to assess the proper order of magnitude of those parameters by comparison of the dynamics of the process implied by the model with the observed post-synaptic potentials. The effect of synaptic depression has been captured in the simulations. The presented approach allowed us to verify to what extent the presynaptic transport can be explained by the diffusive mechanism. Furthermore, the sensitivity of the model to release rate and the synthesis rate is considered. Moreover, the algebraic models of the diminishment of released neurotransmitter amounts were proposed and tested, showing a good accuracy. Various geometrical aspects of the dynamics were studied. In particular, the influence of the geometry of the synthesis region was examined. In the paper, the aspects of numerical simulations are studied as well. Namely, the quality of the generated mesh was discussed. The results of the simulations were compared with the results of measurements and observations and will be later contrasted with more complex models. (c) 2019 The Authors. Published by Elsevier B.V. on behalf of Nalecz Institute of Biocybernetics and Biomedical Engineering of the Polish Academy of Sciences.