Timecourse of axonal and dendritic alterations following somatodendritic exposure to kainic acid. Top panel show schematic of neuronal arrangement in microfluidic chambers. Β-III tubulin (axonal) and MAP2 (dendrite) immunoreactivity indicated beading of a small number of both distal axons and distal dendrites by 1 hour post exposure to kainic acid. By 6 hours extensive axonal beading was present and dendritic arbours were reduced in area. By 16 hours axons were fragmented, although β-III tubulin immunoreactivity was still present within axonal fragments and MAP2 immunoreactivity was restricted to neuronal soma and a small number of short dendrites. Arrows indicate beading; arrow head indicates shortened dendrites. Scale bar: 20 μm.