Table 1. Distribution of neuronal markers.

N7 cells were grown for three days in defined neural medium in the presence of Dox, followed by two days without Dox in defined neural medium ± 1 µM retinoic acid (RA). At least 1000 cells from 10 randomly selected fields in 3 replicate dishes were scored for immunoreactivity to the markers indicated and divided by the total cell number in each field determined by Hoechst nuclear staining. The data presented are the overall means for each treatment group ± s.e.m. across the 3 replicates. P values are based on results of ANOVA, followed by pairwise Student’s t-test.

TuJ1/Peripherin staining	+RA	−RA	+RA vs. −RA p=
%TuJ1+	69.2±1.2	63.7±1.5	<0.001
%Peripherin+ somata	3.5±0.3	2.9±0.2	0.022
TuJ1+ Peripherin+	20.9±1.6 : 1	22.7±1.3 : 1	0.143
Brn3a/Peripherin staining	+RA	−RA	+RA vs. −RA p=
%Peripherin+ somata	3.4±0.4	2.9±0.2	0.032
%Brn3a+	17.8±1.0	16.1±1.0	0.063
% of Peri+ also Brn3a+	96.9±2.4	96.8±2.5	0.4755
Brn3a/Isl1 staining	+RA	-RA	+RA vs. −RA p=
%Brn3a (total)	18.1±0.9	16.7±1.1	0.067
Brn3a+/Isl1+	7.4±0.7	6.5±0.5	0.065
Brn3a+/Isl1−	11.3±0.8	10.3±1.2	0.168
%Isl1+ (total)	7.4±0.6	6.5±0.5	0.095
Isl1+/Brn3a−	0.2±0.1	0.1±0.1	0.191