tailieunhanh - Báo cáo hóa học: " Diffusion laws in dendritic spines"

Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Diffusion laws in dendritic spines | Journal of Mathematical Neuroscience 2011 1 10 0 The Journal of Mathematical Neuroscience DOI 2190-8567-1-10 RESEARCH Open Access Diffusion laws in dendritic spines David Holcman Zeev Schuss Received 1 August 2011 Accepted 27 October 2011 Published online 27 October 2011 2011 Holcman Schuss licensee Springer. This is an Open Access article distributed under the terms of the Creative Commons Attribution License Abstract Dendritic spines are small protrusions on a neuronal dendrite that are the main locus of excitatory synaptic connections. Although their geometry is variable over time and along the dendrite they typically consist of a relatively large head connected to the dendritic shaft by a narrow cylindrical neck. The surface of the head is connected smoothly by a funnel or non-smoothly to the narrow neck whose end absorbs the particles at the dendrite. We demonstrate here how the geometry of the neuronal spine can control diffusion and ultimately synaptic processes. We show that the mean residence time of a Brownian particle such as an ion or molecule inside the spine and of a receptor on its membrane prior to absorption at the dendritic shaft depends strongly on the curvature of the connection of the spine head to the neck and on the neck s length. The analytical results solve the narrow escape problem for domains with long narrow necks. 1 Introduction Recognized more than 100 hundreds years ago by Ramón y Cajal dendritic spines are small terminal protrusions on neuronal dendrites and are considered to be the D Holcman Institute for Biology IBENS Group of Computational Biology and Applied Mathematics Ecole Normale Supérieure 46 rue d Ulm 75005 Paris France e-mail holcman@ D Holcman Department of Applied Mathematics UMR 7598 Université Pierre et Marie Curie Boite Courrier 187 75252 Paris France Z Schuss Department of Mathematics Tel-Aviv University Tel-Aviv 69978 Israel e-mail schuss@ 0 Springer Page 2of14 Holcman Schuss .