Trumbore D C, Heideger W J, Beach K W
Calcif Tissue Int. 1980;32(2):159-68. doi: 10.1007/BF02408535.
The control of ion fluxes to and from bone has important implications to mineralization and calcium homeostasis. Since ionic transport frequently results in an electrical potential difference across the layer of cells lining bone surfaces, knowledge of this potential is critical to understanding the means of regulation of ionic concentrations in the interior bone fluid phase. This work presents a determination of a metabolism-related electrical potential difference by a thermodynamic argument based on the distribution of charged and uncharged tracers between the bone extracellular fluid compartment and the bathing medium. For embryonic chick calvaria whose viability was assured by oxygen consumption measurements, an electrical potential of 4 mV was determined, positive with respect to the bone fluid compartment. This measurement is shown to be consistent with the active transport of K+ ion into the interior of bone; the potential developed by this transport process will then exclude from the interior phase a passively leaked Ca2+ ion.
控制进出骨骼的离子通量对矿化作用和钙稳态具有重要意义。由于离子运输常常会在骨表面衬里细胞层上产生电势差，了解这一电势对于理解调节骨内液相离子浓度的方式至关重要。这项工作通过基于带电和不带电示踪剂在骨细胞外液隔室与外部浴液之间的分布的热力学论证，确定了与代谢相关的电势差。对于通过耗氧量测量确保其活力的胚胎鸡颅骨，确定其电势为4毫伏，相对于骨液隔室为正。该测量结果表明与钾离子主动转运到骨内部一致；由该转运过程产生的电势随后将被动泄漏的钙离子排除在内部相之外。
