Nuclear Architecture in the Medulla Oblongata of the Adult African Giant Pouched Rat (Cricetomys gambianus, Waterhouse - 1840) / Arquitectura Nuclear en la Médula Oblonga de la Rata Gigante de Carillos Africana Adulta (Cricetomys gambianus, Waterhouse - 1840)

The architecture of cranial and non-cranial nerve nuclei in the medulla oblongata of the African giant pouched rat was studied by means of light microscopy. Serial sections of the medulla oblongata, in coronal and saggital planes, were stained with the cresyl fast violet and silver stains, respectively. Sections in the saggital plane were used as a guide, while coronal sections were used to identify the nuclei in the rostrocaudal extent of the medulla oblongata. With the obex serving as the landmark, nuclei rostral and caudal to the obex were delineated. Cranial nerve nuclei whose architecture were defined were the motor nucleus of hypoglossal nerve, motor nucleus of vagus nerve, cochlear nucleus, vestibular nucleus and nucleus ambiguus, while non-cranial nerve nuclei identified were the olivary nucleus, solitary tract nucleus, gracile nucleus, cuneate nucleus, spinal nucleus of trigeminal nerve, motor nucleus of corpus trapezoideum, lateral nucleus of reticular formation and gigantocellular nucleus. The olivary nucleus was the most prominent nucleus, while the solitary tract nucleus was faint, and thus, less developed. The rostrocaudal extent of the solitary tract nucleus, olivary nucleus and motor nucleus of hypoglossal nerve were 3.81 mm, 2.36 mm and 3.50 mm in length, respectively. The prominent olivary nucleus, pyramidal tract and vestibular nucleus are indicative of a good motor coordination and balance, while the poorly developed solitary tract nucleus points to less efficient autonomic functions in this rodent. The present study will serve as a lead for future neuro-behavioural studies necessary for an effective domestication and adaptation of the African giant pouched rat.

Se estudió mediante microscopía de luz la arquitectura de los núcleos de los nervios craneales y no craneales en la médula oblonga de la rata gigante de carillos africana. Secciones seriales de la médula oblonga, en los planos coronal y sagital, se tiñeron con violeta de cresil rápida y tinción de plata, respectivamente. Como guías se utilizaron secciones en el plano sagital, mientras que, secciones coronales se utilizaron para identificar los núcleos en la extensión rostrocaudal de la médula oblonga. Fueron delineados, con el óbex que actúa como punto de referencia, los núcleos rostral y caudal a éste. Los núcleos de los nervios craneales cuya arquitectura se definió fueron los núcleos: motor del nervio hipogloso, motor del nervio vago, coclear, vestibulares y ambiguo, mientras que los núcleos de los nervios craneales no identificados fueron: olivar, del tracto solitario, grácil, cuneiforme, espinal del nervio trigémino, motor del cuerpo trapezoide, lateral de la formación reticular y gigantocelular. El núcleo olivar fue el más importante, mientras que el núcleo del tracto solitario fue tenue, y por lo tanto, menos desarrollado. Las longitud rostrocaudal de los núcleos del tracto solitario, olivar y motor del nervio hipogloso fueron 3,81 mm, 2,36 mm y 3,50 mm, respectivamente. El núcleo prominente olivar, el tracto piramidal y el núcleo vestibular fueron indicativos de una buena coordinación motora y equilibrio, mientras que el escaso desarrollo de los puntos del núcleo del tracto solitario indican una menor eficiencia de las funciones autonómicas en este roedor. El presente estudio servirá para conducir futuros estudios sobre el neuro-comportamiento necesario para una efectiva domesticación y adaptación de la rata gigante de carillos africana adulta.

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

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.

Localization of Nerves Innervating Submandibular Gland in the Rat Brain Stem Using Cholera Toxin B Subunit / 대한해부학회지

The purpose of this study is to investigate the origin of neurons and afferent fibers projecting to submandibular gland by means of retrograde transport of Cholera Toxin B Subunit (CTB). CTB was injected into the both side submandibular gland or left side submandibular gland. In the rat brain stem, neurons were labeled with CTB in superior salivatory nucleus (SSN), facial nucleus, caudal region of hypoglossal nucleus, lateral horn of spinal cervical segment and their afferent fibers in nucleus tractus solitarius. At the most rostal level of SSN, the labeled cells were seen in lateral aspect of pontine reticular formation. At the level of facial nerve that traverse the dorsal part of the spinal trigeminal tract, the labeled cells of SSN extended to the anterolateral direction of lateral aspect of reticular formation. At the level of facial nucleus, the labeled cells of SSN were seen in the area of caudal prologation of the same region of rostral ones, but decreased in cell number. In the facial nucleus, the labeled cells were confined in central part of facial nucleus. In the first and second spinal cervical segment, the labeled cells were seen in the intermediomedial nucleus of lateral horn. The labeled nerve fibers in nucleus tractus solitarius were seen at the level of the 4th ventricle which the medial border of the nucleus tractus solitarius meets. Injection of CTB into the left submandibular gland labeled their neurons on the left and right superior salivatory nucleus (SSN), but other labeled cells and fibers were localized only on the left side.