Rat Brain Hippocampus Neurons from rat (E18, 19) brain are cell suspensions of high quality primary embryonic brain neuronal cells (including glia) prepared by standardized methods, and are ready for immediate culture. Each vial of cells contains approximately 1 million viable cells. This will seed into 5 or more wells of a 24-well plate and 25 or more wells of a 96-well plate using the recommended plating densities and medium. Cell death will occur during the first few days after plating and debris will be observed. This is normal. After approximately 4 days in culture, the cells will form a neurite network and by the 7th day, debris will be minimal.