AUTHOR=Hartnell David , Andrews Wendy , Smith Nicole , Jiang Haibo , McAllum Erin , Rajan Ramesh , Colbourne Frederick , Fitzgerald Melinda , Lam Virginie , Takechi Ryusuke , Pushie M. Jake , Kelly Michael E. , Hackett Mark J. 

TITLE=A Review of ex vivo Elemental Mapping Methods to Directly Image Changes in the Homeostasis of Diffusible Ions (Na+, K+, Mg2 +, Ca2 +, Cl–) Within Brain Tissue

JOURNAL=Frontiers in Neuroscience

VOLUME=13

YEAR=2020

URL=https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2019.01415

DOI=10.3389/fnins.2019.01415

ISSN=1662-453X

ABSTRACT=<p>Diffusible ions (Na<sup>+</sup>, K<sup>+</sup>, Mg<sup>2+</sup>, Ca<sup>2+</sup>, Cl<sup>–</sup>) are vital for healthy function of all cells, especially brain cells. Unfortunately, the diffusible nature of these ions renders them difficult to study with traditional microscopy <italic>in situ</italic> within <italic>ex vivo</italic> brain tissue sections. This mini-review examines the recent progress in the field, using direct elemental mapping techniques to study ion homeostasis during normal brain physiology and pathophysiology, through measurement of ion distribution and concentration in <italic>ex vivo</italic> brain tissue sections. The mini-review examines the advantages and limitations of specific techniques: proton induced X-ray emission (PIXE), X-ray fluorescence microscopy (XFM), secondary ion mass spectrometry (SIMS), laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and the sample preparation requirements to study diffusible ions with these methods.</p>