In situ hybridization histochemistry for rat Cyp2j4 mRNA in brain 7 days after TBI. Representative fields of injured and contralateral (A) parietal cortex; (B) piriform cortex; (C) hippocampal dentate gyrus. Note the apparent loss of pyramidal neurons in the ipsilateral dentate hilar region. Little staining was observed in the corpus callosum or other white matter structures. Some microvascular profiles appeared to stain positive in these non-perfused fresh frozen brain sections. Studies were carried out starting anterior to the site of injury, staining every sixth section through the injured volume (bregma −1.8 mm to approximately −4.5 mm, according to the coordinates of Paxinos and Watson ). High stringency hybridization and washes were performed as described in Section In situ hybridization histochemistry.