The localization of basic fibroblast growth factor (FGF-2) in rat submandibular glands

The immunohistochemical localization of basic fibroblast growth factor (FGF-2) in the submandibular glands of the rat was investigated by use of an antiserum to FGF-2. Nerve fiber bundles with FGF-2-immunoreactivity were found in association with interlobular ducts and blood vessels; they dissociated into single immunoreactive nerve fibers perhaps to terminate in proximity to acinar cells, or to form a reticular fiber network within the tunica adventitia of blood vessels. The FGF-2-immunoreactive neurons were located in the submandibular ganglia, but not in the superior cervical ganglia; hence, at least some of these immunoreactive nerve fibers probably come from the submandibular ganglia and are of parasympathetic origin. Most of the epithelial cells of the intercalated and collecting ducts showed notable FGF-2 immunoreactivity. The characteristic distribution of FGF-2 immunoreactivity in both the neuronal and epithelial tissues of the salivary glands suggests a role of this growth factor in complex physiological processes within the salivary glands.