CGRP expression in rat STN. (A) CGRP staining of rat STN. Immunopositive fibers are mostly found in the superficial laminae (arrow) and some fibers extending into the spinal trigeminal tract region (arrow head). Higher magnification shows the staining pattern in detail around fiber bundles and displaying "pearl-like" immunoreactivity in the fibers. (B) CGRP positive neurons (visualized with two different primary antibodies; green and red) in the region of the inferior olive and hypoglossal nucleus (arrows). The staining displays granular-like pattern in the cytoplasm. CGRP positive fibers are also found close to the central canal (arrow heads).