Figure 1.

A, The isotropic fractionator is a 10-step method that requires little material and allows rapid determination of the total number of cells (2 h from steps 2-8) and total numbers of neuronal and non-neuronal cells (24 h from steps 2-10) in aldehyde-fixed brain tissue. Fr, Fraction. B, C, Appearance of isotropic suspensions of DAPI-stained nuclei prepared from unfixed (B) or paraformaldehyde-fixed (C) adult rat cortex, shown at the same magnification. Scale bars, 50 μm. Although complete dissociation of unfixed tissue leads to nuclear destruction (B), fixed, dissociated nuclei are intact and have preserved morphology (C).