Brightfield photomicrographs of cyclooxygenase-2 (COX-2) staining in a normal rat. A Low-power photomicrograph of 40-μm coronal section using a 200-mm zoom lens. 8×. Observe that staining intensity is equal in the left and right neocortices. Neocortical COX-2 immunoreactivity (IR) was most intense in layers II and III. B,C: Medium-power photomicrographs of COX-2 IR in the left (B) and right (C) entorhinal cortices. 60 ×.D,E: High-power photomicrographs from left (D) and right (E) entorhinal cortices taken at 378×. Scale bars. = 100 μm in B,C, 15 μm in D,E.