Directional movement of microglial processes towards the surface in acute brain slices requires ATP and adenosine.

<p>(A) Representative rendered images of 3-dimensional confocal fluorescence images of iba-1/Alexa fluo-488 labelled microglia in acute brain slices of wild-type (left) and cd39^-/- (right) mice are shown. The green lines show the processes, and the cell soma is labeled in pink. In wild-type and cd39^-/- mice, the microglial processes are randomly distributed around the cell soma in control conditions. In wild-type mice but not in cd39^-/- mice, ATP (10 μM) induced re-orientation and elongation of microglial processes towards the slice surface (left two images). Dipyridamole (dip, 20 μM) restored the ability of cd39^-/- microglia to re-orient the processes in an ATP gradient. On the Z axis, the coordinate of the slice surface is zero (0). (B) The bars show a distribution of the cumulative number of process terminal points between two compartments: above (grey) and below (white) the position of the microglia soma with respect to the slice surface. ^ns denotes p > 0.5, *** denotes p < 0.001.