Fig. 2.

Signal level and pattern analysis of differentially expressed genes. (A) Reverse Northern blot analysis and classification of differentially expressed genes by DAzLE. Two micrograms of DNA of each clone was dot-blotted onto a nylon membrane and probed with [³²P]cDNA synthesized from mRNA samples of KCl, KCl plus l-NAME, or l-NAME-treated rat cortical neurons. Clones (469 of 980) identified from primary screening are confirmed to show differential expression by reverse Northern blot analysis. These experiments were performed twice under the same conditions. (B) Quantitative changes in gene expression of 469 clones (KCl stimulation of rat cortical neurons). The relative expression level of these genes was normalized by the average value of 14 clones including GAPDH, which exhibit stable expression under KCl treatment at different time points. The average value of levels of unstimulated and N-Arg treatment at 6 h and 24 h were also used as controls.