Primary Rat Cortical Cells are live neurons isolated from micro-surgically dissected regions of day 18 embryonic Sprague/Dawley or Fischer 344 rat brain. These cells are prepared fresh each week and shipped in a nutrient rich medium that keeps the cells alive for up to 14 days under refrigeration. Storage: Shipped refrigerated. Cells are stable for up to 2 weeks when stored at 4-8ºC. It is recommended to plate the cells as soon as possible after receiving cells.