Muscarinic activation of rhombencephalic neurones controlling oesophageal peristalsis in the rat

Bieger, D.

doi:10.1016/0028-3908(84)90088-1

Cited by 75 publications

(56 citation statements)

References 26 publications

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“…28,30,32,38 The neurons that are involved in the reflex control of swallowing are linked synaptically with both peripheral afferents and cortical swallowing-associated areas. 28,30,39 Premotor neurons located in and around the NTS and the NA are connected with different cranial motor neuron pools associated with swallowing. 32,38,39,40 In LMI, primarily these premotor neurons and their connections appear to be affected.…”

Section: Discussionmentioning

confidence: 99%

“…28,30,39 Premotor neurons located in and around the NTS and the NA are connected with different cranial motor neuron pools associated with swallowing. 32,38,39,40 In LMI, primarily these premotor neurons and their connections appear to be affected. Consequently, an acute disconnection could occur between the ipsilateral dorsal swallowing center, ie, the NTS, and the contralateral side of the center of swallowing at the medulla oblongata.…”

Section: Discussionmentioning

confidence: 99%

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Dysphagia in Lateral Medullary Infarction (Wallenberg’s Syndrome)

Aydoğdu

Ertekin

Tarlacı

et al. 2001

Stroke

129

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Background and Purpose-We have investigated the pathophysiological mechanisms of dysphagia in Wallenberg's syndrome (WS) that are due to lateral medullary infarction (LMI). Methods-Twenty patients with WS were evaluated by means of clinical and electrophysiological methods that measured the oropharyngeal phase of voluntarily initiated swallowing. For comparison, 22 patients with unilateral hemispheric infarction were investigated during the acute stage of stroke, and 4 patients with unilateral peripheral 9th and 10th cranial nerve palsies were studied. Age-matched 30 healthy control subjects were also included in the study. Results-It was found that dysphagia was clinically more severe in WS patients than in the patients in the other groups.The pharyngeal phase of swallowing was predominantly impaired, whereas in patients with hemispheric stroke, dysphagia was related only to the delay of triggering of the voluntarily induced swallowing. In WS patients, the swallowing reflex was extremely slow in spite of the unilateral involvement due to LMI, whereas the pharyngeal phase of reflex swallowing remained within normal limits in patients with unilateral hemispheric stroke and patients with unilateral peripheral 9th and 10th cranial nerve palsies. Conclusions-Although in WS the lesion due to LMI is unilateral, its effect on oropharyngeal swallowing is bilateral. In LMI, primarily the premotor neurons in the nucleus ambiguus and their connections seem to be affected. Consequently, a disruption and/or disconnection of their linkage to swallowing-related cranial motor neuron pools bilaterally and to the contralateral nucleus ambiguus could produce the swallowing disorders in WS. However, the remaining intact ipsilateral premotor neurons and the contralateral center in the medulla oblongata may eventually begin to operate and overcome the severity and long-term persistence of dysphagia.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Dysphagia in Lateral Medullary Infarction (Wallenberg’s Syndrome)

Aydoğdu

Ertekin

Tarlacı

et al. 2001

Stroke

129

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“…The presence of numerous NADPH-diaphorase-positive neurons in the subnucleus centralis is the case for a wide range of different species (Bieger and Sharkey, 1993). This histochemical marker appears to delineate the subnucleus, which has otherwise been defined only by its projections to the rostral nucleus ambiguus (Bieger, 1984;Cunningham and Sawchenko, 1989) and afferents from the esophagus (Altschuler et al, 1989). The majority of NOS-containing neurons in the subnucleus centralis project to motor neurons in the nucleus ambiguus that innervate the esophagus (Wiedner et al, 1995), and probably act as relay neurons between esophageal afferent and efferents (Gai et al, 1995).…”

Section: Relationship Of Nos-containing Dmv Neurons To Gastrointestinmentioning

confidence: 97%

“…This agent has frequently been used as a competitive antagonist of NOS, although it may also have antimuscarinic effects (Buxton et al, 1993). It is unlikely that the increase in intragastric pressure noted upon microinjection of L-NAME into the DVC is due to its potential antimuscarinic actions, because acetylcholine microinjected into the NTS has no effect on gastric motor activity (Spencer and Talman, 1986) and increased esophageal peristalsis (Bieger, 1984).…”

Section: Physiological Significance Of No In the Dvcmentioning

confidence: 98%

“…In the NTS, sensory afferents from the esophagus terminate primarily in the subnucleus centralis (Altschuler et al, 1989). This subnucleus projects to motor and premotor neurons within and around the nucleus ambiguus and forms part of the reflex pathways controlling swallowing (Bieger, 1984;Cunningham and Sawchenko, 1989). The densest concentration of afferents from the stomach are found in a cell-poor region in the dorsomedial NTS, termed the subnucleus gelatinosus (Shapiro and Miselis, 1985;Altschuler et al, 1989), with a lesser representation in the medial and commissural subnuclei.…”

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Distribution of nitric oxide synthase in rat dorsal vagal complex and effects of microinjection of nitric oxide compounds upon gastric motor function

et al. 1997

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Nitric oxide (NO) has received attention as a vagal nonadrenergic-noncholinergic (NANC) mediator of gastrointestinal relaxation. The dorsal vagal complex (DVC) is the primary hindbrain site of vagal control of the gastrointestinal tract, and yet the subnuclear distribution of NO and its physiological effects have not been analyzed in this nucleus. Therefore, this study estimates the relative number of NO synthase (NOS)-containing neurons in subnuclear regions of the DVC, identifies NOS-containing vagal abdominal preganglionic neurons in the dorsal motor nucleus of the vagus, and defines a role of NO in the DVC in control of gastric motor function. The location of NADPH-diaphorase-positive staining (a marker of NOS activity) and NOS immunoreactivity overlap in the DVC. In the dorsal motor nucleus of the vagus there are positively stained cells caudal to the obex and at its most rostral extent, but not at the intermediate level. Intraperitoneal fluorogold combined with NADPH-diaphorase activity labels approximately 5% and 15% of fluorogold-immunoreactive cells in the caudal and rostral dorsal motor nucleus of the vagus, respectively. Thus, a portion of NOS-containing neurons are preganglionic vagal neurons projecting to the abdominal viscera. In the nucleus tractus solitarius, the majority of NADPH-diaphorase-positive cells are within the centralis, medial, and ventral/ventrolateral subnuclei. Fiber/terminal staining is present in the subnucleus centralis, subnucleus gelatinosus, subpostremal zone, and the medial nucleus tractus solitarius. The presence of NOS terminal staining implicates NO in afferent control of gastric function in the DVC (e.g., vago-vagal circuits in subnucleus gelatinosus). To determine a role of NO in the DVC, NO-related agents were microinjected into the DVC in alpha-chloralose-anesthetized rats while recording indices of gastric motor function. L-Arginine, microinjected into the DVC, significantly decreases intragastric pressure (-2.2 +/- 0.4 cm2, N = 12), and this effect is abolished by vagotomy. Microinjection of an NOS inhibitor, NG-nitro-L-arginine methyl ester, increases intragastric pressure (1.9 +/- 0.7 cm2, N = 10), with the greatest effect in the DVC rostral to the obex. Overall, it was concluded that tonic release of NO in the DVC mediates gastric relaxation, at least in anesthetized animals, and NOS-containing preganglionic neurons in the dorsal motor nucleus of the vagus may be "command" NANC neurons which control a variety of gastrointestinal functions.

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Ultrastructural characterization of pharyngeal and esophageal motoneurons in the nucleus ambiguus of the rat

1996

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The viscerotopic organization of the upper alimentary tract has been established in the nucleus ambiguus, but there is little information about the morphology of the individual neurons innervating the pharynx and esophagus. We studied the ultrastructure of pharyngeal (PH), cervical esophageal (CE), and subdiaphragmatic esophageal (SDE) motoneurons labeled by retrogradely transported wheat germ agglutinin conjugated horseradish peroxidase (WGA-HRP) in the compact formation of the nucleus ambiguus. WGA-HRP was injected into the lower pharynx, or the cervical and subdiaphragmatic esophagus of male rats. The retrogradely labeled PH neurons in the rostral portion of the compact formation were large (26.1 x 50.1 microns, 906.7 microns2), polygonal, and contained well-developed cell organelles with a round nucleus. Subsurface cisterns connected with rough endoplastic reticulum were often present near the postsynaptic membrane. Both CE and SDE neurons in the compact formation were medium-sized, round or oval, and contained well-developed cell organelles, although the SDE neuron was significantly larger than the CE neuron (24.9 x 33.6 microns, 593.0 microns2 in the SDE neuron, and 19.5 x 30.2 microns, 440.3 microns2 in the CE neuron). The average number of axosomatic terminals in a sectional plane was largest in PH neurons (29.0), smaller in CE neurons (7.9), and smallest in SDE neurons (4.2). The number of axosomatic terminals containing round vesicles (Gray's type I) was almost equal to that of terminals containing pleomorphic vesicles (Gray's type II) in PH and CE neurons, but there were few Gray's type II axosomatic terminals in SDE neurons. Desmosome-like junctions at somato-somatic or somato-dendritic apposition were often present in the area surrounding SDE neurons. There were also small unlabeled neurons (9.5 x 18.1 microns, 131.8 microns2) in the compact formation of the nucleus ambiguus. The small neurons contained poorly developed cell organelles and an irregular shaped nucleus with invaginated nuclear membrane, and had no Nissl bodies. These results indicate that PH neurons have the characteristics of somatic motoneurons, and that CE and SDE neurons are similar to visceral motoneurons.

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Muscarinic activation of rhombencephalic neurones controlling oesophageal peristalsis in the rat

Cited by 75 publications

References 26 publications

Dysphagia in Lateral Medullary Infarction (Wallenberg’s Syndrome)

Dysphagia in Lateral Medullary Infarction (Wallenberg’s Syndrome)

Distribution of nitric oxide synthase in rat dorsal vagal complex and effects of microinjection of nitric oxide compounds upon gastric motor function

Ultrastructural characterization of pharyngeal and esophageal motoneurons in the nucleus ambiguus of the rat

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