Expression of TLR4 mRNA in neuronal and glial cell cultures. Neuronal, mixed glial, microglial and astrocytic primary cultures were analyzed by RT-PCR for expression of TLR4 and GAPDH mRNAs. cDNA amplification was visualized by agarose gel electrophoresis. Images shown are representative of three experiments carried out on separate cultures. GAPDH, glyceraldehyde 3-phosphate dehydrogenase; TLR4, Toll-like receptor 4.