Numeration of apoptotic astrocytes using immunocytochemistry. Histogram showing the percentage of apoptotic astrocytes relative to the total number of astrocytes after 24 hours of treatment. Mean values and standard errors were calculated for each treatment. Unpaired t tests were used to analyse the significance of differences between pairs of the three treatments. A p value of <0.05 was regarded as statistically significant. p value between controls and QUIN 350 nM, QUIN 500 nM, 1200 nM treated slides were respectively 0.07 (NS), 0.04 (**) and 0.004 (***); and 0.002 (***) between controls and cycloheximide treated slides. p values between QUIN 500 nM, 1200 nM and cycloheximide treated slides were not significantly different.