qRT-PCR studies and Western blot analysis. a GP, GS and GFAP mRNA expression levels were analyzed in cortical neuronal cultures, rat cortex and cerebellum. Ct-values were normalized to GAPDH, β-actin and 18S rRNA. Expression rates of the genes were given as n-fold of the relevant rates in astroglial cultures. Data were shown as means ± SEM (n = 6). b GP protein Western blotting analysis in cortical neuronal cultures, whole rat brain and astroglial cultures. For each protein extract, 2,5 and 1 μg of protein were loaded.