IE gene expression upon BDNF stimulation of primary cortical neurons. (a) Comparison of selected group of genes between trkB+/+ and trkBSHC/SHCmutant mice. The mRNA for the Affymetrix analysis was obtained from E15.5 primary cortical neurons with +/+ or TrkBSHC receptors that were either left unstimulated or stimulated with 50 ng/ml of BDNF for 1 hour after 1DIV. The fold change was averaged from three independent experiments. (b-d) qRT-PCR analysis of the selected BDNF regulated genes. Total mRNA obtained from trkB+/+ or trkBSHC/SHCprimary cortical neurons, either left untreated or treated with 50 ng/ml of BDNF at different time points, were analyzed by qRT-PCR using primers specific for Egr1 (b), Fos (c), and Egr2 (d). After normalization to GAPDH, mRNA levels were expressed relative to the levels obtained from wild-type unstimulated cortical neurons, which were given the arbitrary value of 1. Average values and standard errors were obtained from three independent animals.