Localization of Sensory Neurons Innervating the Rat Intestine Using the Cholera Toxin B Subunit(CTB) and Wheat Germ Agglutinin-Horseradish Peroxidase(WGA-HRP)

Lee, Dong Hyup; Lee, Chang Hyun; Lee, Moo Sam

Abstract

The local arrangement of sensory nerve cell bodies and nerve fibers in the brain stem, spinal ganglia and nodose ganglia were observed following injection of cholera toxin B subunit(CTB) and wheat germ agglutinin-horseradish peroxidase(WGA-HRP) into the rat intestine. The tracers were injected in the stomach(anterior and posterior portion), duodenum, jejunum, ileum, cecum, ascending colon or descending colon. After survival times of 48-96 hours, the rats were perfused and their brain, spinal and nodose ganglia were frozen sectioned(40microM). These sectiones were stained by CTB immunohistochemical and HRP histochemical staining methods and observed by dark and light microscopy. The results were as follows: 1. WGA-HRP labeled afferent terminal fields in the brain stem were seen in the stomach and cecum, and CTB labeled afferent terminal fields in the brain stem were seen in all parts of the intestine. 2. Afferent terminal fields innervating the intestine were heavily labeled bilaterally gelalinous part of nucleus of tractus solitarius(gelNTS), dorsomedial part of gelNTS, commissural part of NTS(comNTS), medial part of NTS(medNTS), wall of the fourth ventricle, ventral border of area postrema and comNTS in midline dorsal to the central canal. 3. WGA-HRP labeled sensory neurons were observed bilaterally within the spinal ganglia, and labeled sensory neurons innervating the stomach were observed in spinal ganglia T2-L1 and the most numerous in spinal ganglia T8-9. 4. Labeled sensory neurons innervating the duodenum were observed in spinal ganglia T6-L2 and labeled cell number were fewer than the other parts of the intestines. 5. Labeled sensory neurons innervating the jejunum were observed in spinal ganglia T6-L2 and the most numerous area in the spinal ganglia were T12 in left and T13 in right. 6. Labeled sensory neurons innervating the ileum were observed in spinal ganglia T6-L2 and the most numerous area in the spinal ganglia were T11 in left and L1 in right. 7. Labeled sensory neurons innervating the cecum were observed in spinal ganglia T7-L2 and the most numerous area in the spinal ganglia were T11 in left and T11-12 in right. 8. Labeled sensory neurons innervating the ascending colon were observed in spinal ganglia T7-L2 in left, and T9-L4 in right. The most numerous area in the spinal ganglia were T9 in left and T11 in right. 9. Labeled sensory neurons innervating the descending colon were observed in spinal ganglia T9-L2 in left, and T6-L2 in right. The most numerous area in the spinal ganglia were T13 in left and L1 in right. 10. WGA-HRP labeled sensory neurons were observed bilaterally within the nodose ganglia, and the most numerous labeled sensory neurons innervating the abdominal organs were observed in the stomach. 11. The number of labeled sensory neurons within the nodose ganglia innervating small and large intestines were fewer than that of labeled sensory neurons innervating stomach These results indicated that area of sensory neurons innervated all parts of intestines were bilaterally gelatinous part of nucleus tractus solitarius(gelNTS), dorsomedial part of gelNTS, commissural part of NTS(comNTS), medial part of NTS, wall of the fourth ventricle, ventral border of area postrema and com NTS in midline dorsal to the central canal within brain stem, spinal ganglia T2-L4, and nodose ganglia. Labeled sensory neurons innervating the intestines except the stomach were observed in spinal ganglia T6-L4. The most labeled sensory neurons from the small intestine to large intestine came from middle thoracic spinal ganglia to upper lumbar spinal ganglia.