Male Sprague-Dawley rats (400±25 g) were anesthetized with sodium pentobarbital. Fluid-percussion head injury with a brief 2.5 atm pressure pulse leading to deformation of underlying brain. 24h after surgery, a 7 mm disk of parieto-occipital cortex, centered on the point of impact of the injury and containing the contusion area, was removed and immediately frozen in chilled 2-methylbutane and then stored at -80C. Cortical tissue from one rat provided sufficient RNA without the need for pooling.
