Piconewton Mechanical Forces Promote Neurite Growth.

Investigations over half a century have indicated that mechanical forces induce neurite growth, with neurites elongating at a rate of 0.1-0.3 μm h(-1) pN(-1) when mechanical force exceeds a threshold, with this being identified as 400-1000 pN for neurites of PC12 cells. In this article, we demonstrate that neurite elongation of PC12 cells proceeds at the same previously identified rate on application of mechanical tension of ∼1 pN, which is significantly lower than the force generated in vivo by axons and growth cones. This observation raises the possibility that mechanical tension may act as an endogenous signal used by neurons for promoting neurite elongation.