  We present investigations on volume regulation and beading shape transitions
in PC12 neurites conducted using a flow-chamber technique. By disrupting the
cell cytoskeleton with specific drugs we investigate the role of its individual
components in the volume regulation response. We find that microtubule
disruption increases both swelling rate and maximum volume attained, but does
not affect the ability of the neurite to recover its initial volume. In
addition, investigation of axonal beading --also known as pearling
instability-- provides additional clues on the mechanical state of the neurite.
We conclude that the initial swelling phase is mechanically slowed down by
microtubules, while the volume recovery is driven by passive diffusion of
osmolites. Our experiments provide a framework to investigate the role of
cytoskeletal mechanics in volume homeostasis.
