Dendritic spine viscoelasticity and soft-glassy nature: balancing dynamic remodeling with structural stability.

TitleDendritic spine viscoelasticity and soft-glassy nature: balancing dynamic remodeling with structural stability.
Publication TypeJournal Article
Year of Publication2007
AuthorsSmith BA, Roy H, De Koninck P, Grütter P, De Koninck Y
JournalBiophys J
Volume92
Issue4
Pagination1419-30
Date Published2007 Feb 15
ISSN0006-3495
KeywordsAnimals, Animals, Newborn, Biomechanical Phenomena, Cells, Cultured, Dendritic Spines, Diffusion, Elasticity, Fluorescence Recovery After Photobleaching, Microscopy, Atomic Force, Models, Biological, Neurons, Rats, Rats, Sprague-Dawley, Viscosity
Abstract

Neuronal dendritic spines are a key component of brain circuitry, implicated in many mechanisms for plasticity and long-term stability of synaptic communication. They can undergo rapid actin-based activity-dependent shape fluctuations, an intriguing biophysical property that is believed to alter synaptic transmission. Yet, because of their small size (approximately 1 microm or less) and metastable behavior, spines are inaccessible to most physical measurement techniques. Here we employ atomic force microscopy elasticity mapping and novel dynamic indentation methods to probe the biomechanics of dendritic spines in living neurons. We find that spines exhibit 1), a wide range of rigidities, correlated with morphological characteristics, axonal association, and glutamatergic stimulation, 2), a uniquely large viscosity, four to five times that of other cell types, consistent with a high density of solubilized proteins, and 3), weak power-law rheology, described by the soft-glassy model for cellular mechanics. Our findings provide a new perspective on spine functionality and identify key mechanical properties that govern the ability of spines to rapidly remodel and regulate internal protein trafficking but also maintain structural stability.

DOI10.1529/biophysj.106.092361
Alternate JournalBiophys. J.
PubMed ID17114228
PubMed Central IDPMC1783894

Funding

Our research endeavors are made possible by the following agencies:

Canadian Institutes of Health Research - Instituts de recherche en santé du Canada Fonds de recherche du Québec – Nature et technologies (FRQNT)Fonds de la recherche en santé du Québec NARSAD Natural Sciences and Engineering Research Council of Canada (NSERC) - Conseil de recherche en sciences naturelles et en génie du Canada (CRSNG)innovation.caHuman Frontier Science Program