Mechanics of Neurons

In recent years it has become increasingly evident that mechanical stimuli play an important role in the differentiation, growth, development, and motility of cells.  Neurons in particular have been shown to be highly sensitive to  mechanical forces – experiments have shown that mechanical forces significantly influence the initiation, growth, and retraction of neurites  in vitro. However,  the in vivo response of neurons to forces has been a largely unexplored area.

We have used our BioMEMS force sensors to explore, for the first time,  the in vivo mechanical behavior of neurons in Drosophila (fruit fly) embryos. Our results show that Drosophila neurons maintain a rest tension (1–13 nN) and behave like viscoelastic solids in response to sustained stretching. More importantly, when their tension is suddenly diminished, neurons contract and actively generate force to restore tension. These observations are remarkably similar to results from in vitro studies and suggest that mechanical tension may strongly influence neuronal behavior in vivo.

a) Phase-contrast image showing a dissected Drosophila embryo and the force sensor. (b) A higher-magnification image of an axon being deformed by a force sensor. (c) Fluorescence image of the Drosophila embryo expressing GFP in all neuronal membranes. (d-f) Mechanical response of the Droshophila neurons showing linear force-deformation behavior (d), force relaxation (e) and force build-up (f). 

Related Publications

1. J. Rajagopalan, A. Tofangchi and M. T. A. Saif, “Drosophila neurons actively regulate axonal tension in vivo,” Biophysical Journal 99, 3208-3215, 2010 (pdf)

2. W. W. Ahmed, J. Rajagopalan, A. Tofangchi and M. T. A. Saif, “Neuromechanics: The role of tension in neuronal growth and memory,” in Nano and Cell Mechanics (Eds. Horacio Espinosa and Gang Bao), John Wiley and Sons, to appear 2012

3.  J. Rajagopalan, A. Tofangchi and M. T. A. Saif, “The role of mechanical tension in neurons,” MRS Symposium Proceedings Vol. 1274, 3-7, 2010 (pdf)

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