<p>Neurons were exposed to L-DOPA (0, 1, 5, 10, 100, 200 µM) in DMEM+5%FBS (A) or astrocyte-conditioned medium (ACM) (B) for 16 hours and then immunostained for MAP-2 antibody as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004593#s2" target="_blank">Materials and Methods</a>.</p