SUBCELLULAR-LOCALIZATION OF ANGIOTENSIN-II IMMUNOREACTIVITY IN THE RAT CEREBELLAR CORTEX

We localized angiotensin II (Ang II) immunoreactivity in the rat cereb ellar cortex with immunogold staining methods. Perfusion fixation with high amounts of glutaraldehyde and the use of cryoultramicrotomy caus ed remarkable changes in immunostaining versus formaldehyde/picric aci d fixation. With the use of monoclonal and polyclonal anti-Ang II, Ang II immunoreactivity was prominent in cerebellar neurons such as Purki nje, granule, basket, and stellate cells. At the subcellular level, th e peptide was clearly localized in nuclei, and in some cell types, suc h as endothelial acid granule cells, it was nearly exclusively present in the transcriptionally active euchromatin. Intracellular Ang II imm unoreactivity was also detected in vesicle-like structures in cytoplas m and mitochondria and at cell-cell contacts. Additional experiments w ith liver and adrenal tissue confirmed the nuclear localization of Ang II immunoreactivity, suggesting a role of Ang II in the regulation of gene transcription.