RT-PCR transcript analysis of TNF-α gene expression. Neonatal rat brain microglia (2.8–5 × 106 cells/culture dish) were treated with (A) LPS [10 ng/mL] or (B) Domoic acid [1 mM] for 1 to 6 hours. (See Materials and Methods). Amplification of TNF-α and S12 genes shows the predicted fragment size after separation on a 1.5 % agarose gel and visualization by SYBRR Gold nucleic acid staining. The S12 rRNA gene product was amplified for 25 cycles and demonstrates equal loading of the gels. Quantification of the TNF-α product was done after 20 cycles (LPS) or 25 cycles (Domoic acid). The cycle numbers used for quantification were shown to be in the linear range.