Arachidonate 12-lipoxygenase is localized in neurons, glial cells, and endothelial cells of the canine brain.

12-Lipoxygenase oxygenates the 12 position of arachidonic acid, producing its 12S-hydroperoxy derivative. We have been interested in the distribution of 12-lipoxygenase in the central nervous system. Previously, by the use of a monoclonal anti-12-lipoxygenase antibody, we proved that one of the arachidonate 12-lipoxygenases existed in canine brain. The present study was therefore designed to elucidate the exact immunohistochemical localization of arachidonate 12-lipoxygenase in canine brain, using a polyclonal anti-12-lipoxygenase antibody. Canine brains were irrigated thoroughly with ice-cold heparinized saline and phosphate-buffered saline to remove blood cells, and then were fixed in 4% periodate-lysine-paraformaldehyde at 4 degrees C for 3 hr. Immunostaining by the indirect method with the peroxidase-labeled antibody was performed for light microscopic observation. The immunohistochemical study demonstrated that many neurons and glial cells in the cerebrum, basal ganglia, and hippocampus were positively stained. Biochemical results as described previously and those of immunohistochemistry indicate that 12-lipoxygenase is definitely localized in various brain parenchymal cells.