Immunohistochemical localization of cytochrome P450 enzymes 2C and 4A in the normal rat brain

OBJECTIVE: To localize cytochrome P450 enzymes 4A and 2C in central nervous cells of normal male rats. METHODS: Eight drug/alcohol untreated normal male rats (150-200 g of body weight) were treated by the optimized perfusion technique, then brain tissues were postfixed, paraffin-embedded and cut into series sections, which were labeled by the improved strept-avidin-biotin complex DAB-nickel enhancer (SABC-DAB-Ni) immunohistochemistry and hematoxylin & eosin (H & E) stain techniques. RESULTS: The immunohistochemical results indicated that P450 2C-11 enzyme was localized in diverse numbers of neurons as well as some neuroglial cells, with focal or defuse distribution in many brain regions such as cerebrum, thalamus, olfactory bulb, hypothalamus, brain-stem, hippocampus, cerebellum, interpositus nucleus, caudate-putamen, and globus pallidus. In contrast, no positive findings of P450 4A-2, 3 and 8 enzymes were obtained in the same animals. With high magnification, 2C-11 protein was able to be roughly observed on the endoplasmic reticulum of the rat neurons. CONCLUSIONS: P450 2C-11 protein, rather than P450 4A-2, 3 and 8, may be a candidate of brain P450 enzymes in the normal male rats.