5.2. Expression of ornithine decarboxylase and antizyme in the rat brain (III)
In order to obtain detailed expression patterns for ODC and antizyme in the rat brain and to compare their expression we employed both in situ hybridization and immunocytochemistry. In situ hybridization showed that ODC and antizyme mRNAs are widely expressed in the brain. The hybridization signal for ODC mRNA was clearly lower than that of antizyme mRNA in all areas investigated, therefore twice as long exposure time was used for ODC mRNA than for antizyme mRNA. The highest expression for both genes was detected in the cerebellar cortex, hippocampus, hypothalamic paraventricular and supraoptic nuclei, locus coeruleus, olfactory bulb, piriform cortex and pontine nuclei (Table I). Considering larger brain regions, thalamus showed lowest expression for both mRNAs. The ODC and antizyme mRNA-expressing cells were large indicating that they were very likely neurons.
Immunocytochemistry confirmed the results of in situ hybridization. Immunoreactivity for both ODC and antizyme was detected widely. ODC antibody displayed mainly cytoplasmic staining in all areas, whereas antizyme protein had two distinct patterns of subcellular localization. In most regions of brain, the antizyme staining was localized in the cytoplasm, as expected. However, antizyme was predominantly detected in the nerve cell nuclei in some areas including the cerebellar cortex, anterior olfactory nucleus, frontal cortex, cingulate cortex, the central nucleus of amygdala, ventromedial hypothalamic nucleus, anterior hypathalamic area, ventroposterior and ventrolateral thalamic nucleus, cochlear nuclei and trapezoid body.
