Kinetics of glutamate (5 mM) treatment on Fas protein levels in primary cortical cells. Cortical cells isolated from 19 day old fetal rat brains were cultured for 7 days and treated with 5 mM glutamate for the indicated times. Cells were collected and total protein was extracted. Fas receptor protein levels were determined by Western blot analysis as described under Figure 6. The results show that glutamate has no significant effects on Fas receptors up to 24 h of treatment. Data are the mean (± SEM) from 3 experiments.