Ultrastructural comparison of dendritic spine morphology preserved with cryo and chemical fixation

Tamada, Hiromi (Laboratory of Sensory Processing, Brain Mind Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland ; Biological Electron Microscopy Facility, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland ; Functional Anatomy and Neuroscience, Graduate School of Medicine, Nagoya University, Nagoya, Japan ; Japan Society of the Promotion of Sciences (JSPS), Tokyo, Japan) ; Blanc, Jerome (Biological Electron Microscopy Facility, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland) ; Korogod, Natalya (Biological Electron Microscopy Facility, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland ; HESAV School of Health Sciences, HES-SO University of Applied Sciences and Arts Western Switzerland) ; Petersen, Carl CH (Laboratory of Sensory Processing, Brain Mind Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland) ; Knott, Graham W (Biological Electron Microscopy Facility, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland)

Previously, we showed that cryo fixation of adult mouse brain tissue gave a truer representation of brain ultrastructure in comparison with a standard chemical fixation method (Korogod et al., 2015). Extracellular space matched physiological measurements, there were larger numbers of docked vesicles and less glial coverage of synapses and blood capillaries. Here, using the same preservation approaches, we compared the morphology of dendritic spines. We show that the length of the spine and the volume of its head is unchanged; however, the spine neck width is thinner by more than 30% after cryo fixation. In addition, the weak correlation between spine neck width and head volume seen after chemical fixation was not present in cryo-fixed spines. Our data suggest that spine neck geometry is independent of the spine head volume, with cryo fixation showing enhanced spine head compartmentalization and a higher predicted electrical resistance between spine head and parent dendrite.


Article Type:
scientifique
Faculty:
Santé
School:
HESAV
Institute:
Unité de recherche en santé, HESAV
Date:
2020-12
Pagination:
15 p.
Published in:
eLife
Numeration (vol. no.):
2020, vol. 9, art. e56384
DOI:
ISSN:
2050-084X
Appears in Collection:



 Record created 2021-01-28, last modified 2021-02-05

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