Localization of Nerves Innervating Sublingual Gland in the Rat Brain Stem Using Cholera Toxin B Subunit

Han, Eui Hyeog; Yang, Chung Yong; Lee, Moo Sam

Abstract

In the rat brain stem, the nerves innervating sublingual gland was studied with submandibular gland together. Cholera Toxin B subunit (CTB), neural tracer, is not yet used to study the sublingual gland. The purpose of this study is to investigate the origin of neurons and afferent fibers projecting to sublingual gland by means of retrograde transport of CTB. CTB was injected into the sublingual gland. In the rat brain stem, neurons were labeled with CTB in superior salivatory nucleus (SSN), inferior salivatory nucleus (ISN), facial nucleus and their afferent fibers in nucleus tractus solitarius. At the rostal level of SSN, the labeled cells were found in lateral aspect of pontine reticular formation. At the level of facial nerve that transverse the dorsal part of the spinal trigeminal tract, the labeled cells of SSN extended in the area of facial nerve fibers. Labeled cells were also seen at the level of internal genu of facial nerve. In ISN at the level of facial nerve that traverse the dorsal part of the spinal trigeminal tract, the labeled cells were seen in the anterolateral direction of lateral aspect of reticular formation. In the facial nucleus, the labeled cells were confined in central part of facial nucleus. The labeled nerve fibers in nucleus tractus solitarius were seen in the level at which the medial border of the nucleus tractus solitarius meets the 4th ventricle.