Representation of the cecum in the lateral dorsal motor nucleus of the vagus nerve and commissural subnucleus of the nucleus tractus solitarii in rat

Abstract

Motor fibers of the accessory celiac and celiac vagal branches are derived from the lateral columns of the dorsal motor nucleus of the vagus nerve. These branches also contain sensory fibers that terminate within the nucleus of the tractus solitarii. This study traces the innervation of the intestines by using the tracer cholera toxin-horseradish peroxidase. In 53 rats, the tracer was injected into either the stomach, duodenum, jejunum, terminal ileum, cecum, or ascending colon. With all cecal injections, prominent retrograde labeling of cell bodies occurred bilaterally in the lateral columns of the dorsal motor nucleus of the vagus nerve above, at, and below the level of the area postrema. Dendrites of laterally positioned neurons projected medially and rostrocaudally within the dorsal motor nucleus of the vagus nerve and dorsomedially into both the medial subnucleus and parts of the commissural subnucleus of the nucleus of the tractus solitarii. Sensory terminal labeling occurred in the dorsolateral commissural subnucleus at the level of the rostral area postrema and the medial commissural subnucleus caudal to the area postrema. Additionally, there was sensory terminal labeling within a small confined area of the dorsomedial zone of the nucleus of the tractus solitarii immediately adjacent to the fourth ventricle at a level just anterior to the area postrema. Stomach injections labeled motoneurons of the medial column of the entire rostrocaudal extent of the dorsal motor nucleus of the vagus nerve and a sensory terminal field primarily in the subnucleus gelatinosus, with less intense labeling extending caudally into the medial and ventral commissural subnuclei. Dendrites of gastric motoneurons project rostrocaudally and mediolaterally within the dorsal motor nucleus of the vagus nerve and dorsolaterally within the nucleus of the tractus solitarii. They are most pronounced at the level of the rostral area postrema where many dendrites course dorsolaterally terminating primarily within the subnucleus gelatinosus. Injections of the duodenum labeled a small number of the cells within the medial aspects of the dorsal motor nucleus of the vagus nerve. Jejunal, ileal, and ascending colon injections labeled cells sparsely within the lateral aspects of the dorsal motor nucleus of the vagus nerve bilaterally. No afferent terminal labeling was evident after injection of these areas of the bowel.(ABSTRACT TRUNCATED AT 400 WORDS)

Localization of Sympathetic, Parasympathetic and Sensory Neurons Innervating the Distal Ileum of the Cattle

“…These neurons are the second group of extrinsic innervation to the ileum. Parasympathetic preganglionic neurons in the DMNV projected to the duodenum, jejunum and ileum in the rat [1,33] and cat [26]. However, the number of labeled neurons after injections into the small intestine was much smaller than that after stomach injections [1,26,33].…”

“…After injection of horseradish peroxidase (HRP) into the small intestine of the cat [5], dog [14] and monkey [29], labeled sensory neurons were found in the dorsal root ganglia (DRGs) and/or nodose (vagal distal) ganglion (NG). Parasympathetic preganglionic neurons innervating the small intestine of the rat [1,33] and cat [26] were located in the dorsal motor nucleus of the vagus nerve (DMNV).…”

Ascending Projections from the Area Postrema and the Nucleus of the Solitary Tract of Suncus Murinus

“…Studies on the innervation of the NTS have suggested that functionally classified columns are arrayed rostrocaudally in this nucleus; for example, gustatory afferents occupy the rostral third portion of the column (Whitehead and Frank, 1983; Hamilton and Norgren, 1984), while visceral afferents occupy a more caudal region (Kalia and Mesulam , 1980; Panneton and Loewy, 1980;Ciriello, 1983 Altschuler et al , 1989Altschuler et al , , 1991. Based on neurological studies showing that the NTS controls the gastrointestinal tract via the dorsal motor nucleus of the vagus (DMV) (Morest, 1967;Cottle and Calaresu, 1975;Norgren, 1978;Beckstead et aL, 1980;Rogers et aL, 1980;Arends et al , 1988), and controls the pharynx, larynx, and esophagus via the nucleus ambiguus (Amb) (Morest, 1967;Cottle and Calaresu, 1975 Cunningham et al, 1991), the NTS appears to play an important role as the afferent system of all visceromotor reflexes, including the emetic response.…”

Characterization of neurons of the nucleus tractus solitarius pars centralis

“…The subnuclei of the NTS are viscerotopically organized [1,2,5]; however, the same subnucleus might receive sensory information from more than one peripheral organ [1,[5][6][7]11,16,22,25,30]. The subnucleus centralis (cNTS), however, receives sensory inputs originating almost exclusively from esophageal afferent fibers [1,8,9,16,23], thus, this nucleus may be a possible model for the study of NTS neurons devoted to the control of esophagus-mediated reflexes.…”

“…Vagal sensory afferent fibers enter the brainstem via the tractus solitarius and terminate in a viscerotopically organized manner in the subnuclei of the nucleus tractus solitarius (NTS) [1,2,5]. Although sensory inputs from distinct peripheral organs, such as, for example, the aortic branch and the stomach, do not converge on single NTS neurons [26], the same subnucleus may receive sensory information from more than one peripheral organ.…”