tailieunhanh - Báo cáo y học: " Anomalous ion diffusion within skeletal muscle transverse tubule networks"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: " Anomalous ion diffusion within skeletal muscle transverse tubule networks | Theoretical Biology and Medical Modelling BioMed Central Research Anomalous ion diffusion within skeletal muscle transverse tubule networks Paul R Shorten and Tanya K Soboleva Open Access Address AgResearch Limited Ruakura Research Centre Private Bag 3123 Hamilton New Zealand Email Paul R Shorten - Tanya K Soboleva - Corresponding author Published 17 May 2007 Received 8 March 2007 Theoretical Biology and Medical Modelling 2007 4 18 doi 1742-4682-4-18 Accepted 17 May 2007 This article is available from http content 4 1 18 2007 Shorten and Soboleva licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background Skeletal muscle fibres contain transverse tubular t-tubule networks that allow electrical signals to rapidly propagate into the fibre. These electrical signals are generated by the transport of ions across the t-tubule membranes and this can result in significant changes in ion concentrations within the t-tubules during muscle excitation. During periods of repeated high-frequency activation of skeletal muscle the t-tubule K concentration is believed to increase significantly and diffusive K transport from the t-tubules into the interstitial space provides a mechanism for alleviating muscle membrane depolarization. However the tortuous nature of the highly branched space-filling t-tubule network impedes the diffusion of material through the network. The effective diffusion coefficient for ions in the t-tubules has been measured to be approximately five times lower than in free solution which is significantly different from existing theoretical values of the effective diffusion coefficient that range from 2-3 times lower than in .