Visualization of G_oα subtype guanine nucleotide-binding regulatory protein in the medulla oblongata and pons of the rat

This study reports on the visualization of G_o protein in the medulla oblongata and pons of Sprague-Dawley rats, using a commercially available selective polyclonal antiserum against a 39-kDa protein corresponding to the α subunit of G_o. Specific immunofluorescent-staining was widely distributed in neuropils and neuronal cell bodies but displayed regional heterogeneity. The immunoreactive product exhibited a punctate appearance and was most pronounced in the cell membrane and cytoplasm of the perikarya and proximal dendrites whereas the nucleus remained unstained. Positive immunoreactivity of G_oα was present in nucleus reticularis gigantocellularis, nucleus reticularis paramedialis, nucleus tractus solitarii, nucleus nervi hypoglossi, nucleus raphé pallidus, locus coeruleus, nucleus tractus mesencephali nervi trigemini and nucleus cuneatus. These results provided anatomic evidence to support the participation of G_o protein in both sensory and motor functions that originate from the medulla oblongata and pons of the rat.