primary cultures: age of rat?

[Ken Scholz]

The age at which cultures should be prepared also depends on the types of 
neurons you wish to obtain.  For example, granule cells (hippocampal, just
for the sake of argument) develop much later than the pyramidal cells.
To obtain a culture enriched in granule cells, most workers will prepare
cultures after birth, sometimes several days.  There are also likely
to be differences in the development of pyramidal neurons verses local
circuit neurons.  The same may apply to the cerebellum.  I don't have
first-hand experience with other regions but it is likely that preparing
cultures at different ages will yield different cell types.
-- 
Ken Scholz                    Department of Pharm. and Physiology
kps2 at midway.uchicago.edu      Univ. of Chicago