Brain stem projections of sensory and motor components of the vagus complex in the cat: II. Laryngeal, tracheobronchial, pulmonary, cardiac, and gastrointestinal branches

Abstract

The central sensory and motor connections of various respiratory, cardiovascular, aqd gastrointestinal viscera were analyzed using the transganglionic and retrograde transport of horseradish peroxidase (HRP).In 42 adult cats, we examined the brain stem and peripheral ganglia following microinjections of HRP (10 p1) into individual visceral organs-larynx, extrathoracic trachea, intrathoracic trachea, right main bronchus, right lung (upper lobe), heart, and stomach. Comparison of individual cases led to the conclusion that distinct patterns of sensory and motor projections to the medulla exist for each visceral organ studied.The nucleus of the tractus solitarius (nTS) receives the sensory projections from all the viscera listed above, with two exceptions: (1) a few sensory fibers from the larynx terminate in the ipsilateral spinal tract of the trigeminal nerve (spV), and (2) some sensory fibers from the bronchus, lung, and stomach terminate in the area postrema (ap). Within the nTS, the sensory fibers from each visceral organ terminate in a number of subnuclei. The dnTS, mnTS, and ncom receive sensory projections from all the viscera studied. The remaining five subnuclei (dlnTS, ni, nI, vlnTS, vnTS) of the nTS are not connected to all viscera, and the density of projections to these regions varies for different viscera. However, there does not seem to be any specific region of the medulla which is devoted entirely to receiving the sensory fibers from a particular visceral organ. Rather, the rostrocaudal extent of sensory fibers, from most of the viscera studied, spans the entire length of the medulla. Differences in the central representation of viscera were found to be subtle and to lie within the organization of the nuclear subgroups of the nTS. The central representation of unpaired or midline viscera (e.g., trachea and heart) is bilateral for both sensory and motor innervation. However, for unilateral, paired viscera (e.g., bronchi and lungs), it was consistently found that over one third of the sensory and motor representation is contralateral. Control experiments involving vascular injections of HRP excluded the possibility that this contralatera1 labeling could have been due to vascular uptake of the enzyme. The localization of sensory perikarya of visceral afferents in the "principal visceral ganglion" of the vagus-the nodose ganglion-was overlapping, and no well-demarcated regions in the nodose ganglion could be identified that received projections primarily from a given visceral organ.The motor nuclei providing parasympathetic (preganglionic) and somatic motor innervation to the viscera were primarily the dmnX, nA, and nRA. The entire dmnX (extending over 10-15 mm rostrocaudally), contributed fibers to each area injected with HRP, with the exception of the extrathoracic trachea. No region in the dmnX was found where preference was given to a specific viscus. The nA contributed efferents to all the viscera studied, and this contribution came from the 468M. KALIA AND M-M. MESULAM entire 6 mm of n...

Neurogenesis of cough, other airway defensive behaviors and breathing: A holarchical system?

“…However, given that the properties of cough receptors differ significantly from RARs (Canning et al, 2004), the extent to which this previous information on RAR relay neurons will be useful in predicting the behavior of cough receptor second order interneurons is unknown. Based on horseradish peroxidase studies of projections of tracheal afferents (Kalia and Mesulam, 1980), it is likely that cough receptor second order interneurons are located near to or intermingled with RAR relay neurons.…”

Chemical profile of vagal preganglionic motor cells innervating the airways in ferrets: the absence of noncholinergic neurons

“…Recent studies indicate that the iNANC system employs vasoactive intestinal peptide (VIP) (7,16,22,38,47,57), nitric oxide (NO) (4, 30, 36, 44, 51), or both (6, 14 -16, 64) to elicit ASM relaxation. However, the preganglionic origin of neurons containing these relaxing molecules has not been established.The preganglionic motor innervation of the airways arises from the nucleus ambiguus and from the most rostral part of the dorsal motor nucleus of the vagus (DMV) (21,23,27,29,34). Inputs from these preganglionic neurons are carried by the vagal fibers that are thought to synapse with airway ganglionic cells, which in turn modify and distribute central parasympathetic outflow to the effector organs of the airways and lungs (54, 59).…”

“…The preganglionic motor innervation of the airways arises from the nucleus ambiguus and from the most rostral part of the dorsal motor nucleus of the vagus (DMV) (21,23,27,29,34). Inputs from these preganglionic neurons are carried by the vagal fibers that are thought to synapse with airway ganglionic cells, which in turn modify and distribute central parasympathetic outflow to the effector organs of the airways and lungs (54,59).…”

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.…”