title: Differential activation of medullary vagal nuclei during different phases of swallowing in the cat.
abstract: The aim of this study was to identify the medullary vagal nuclei involved in the different phases of swallowing activated physiologically in a species with an esophagus similar to human. In decerebrate cats, the pharyngeal (0.5-1.0 ml water in pharynx (N=6)) or esophageal (1-3 ml air in esophagus (N=5)) phases of swallowing were stimulated separately once per minute for 3 h, and we compared the resulting c-fos immunoreactivity within neuronal cell nuclei of the dorsal motor nucleus (DMN), nucleus tractus solitarius (NTS) and nucleus ambiguus (NA) with a sham control group (N=5). We found that the pharyngeal phase was associated with an elevated number of c-fos positive neurons in the intermediate (NTSim), interstitial (NTSis), ventromedial (NTSvm) subnuclei of the NTS, caudal DMN, and dorsal NA; and the esophageal phase was associated with an elevated number of c-fos positive neurons in the central (NTSce), ventral, dorsolateral, ventrolateral subnuclei of the NTS, rostral DMN, and ventral NA. We concluded that the pharyngeal and esophageal phases of swallowing are associated with different sets of NTS subnuculei; and the DMN and NA may contain functionally different populations of motor neurons situated rostrocaudally and dorsoventrally associated with the different phases of swallowing. The central pattern generator (CPG) for swallowing probably receives significant peripheral feedback, and the NTSvm may participate in the transition of the pharyngeal to the esophageal phase of swallowing.
authors.affiliation: Department of Medicine, MCW Dysphagia Research Laboratory, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA. imlang@mcw.edu
authors.forename: Ivan M
authors.initials: IM
authors.lastname: Lang
authors.forename: Caron
authors.initials: C
authors.lastname: Dean
authors.forename: Bidyut K
authors.initials: BK
authors.lastname: Medda
authors.forename: Muhammad
authors.initials: M
authors.lastname: Aslam
authors.forename: Reza
authors.initials: R
authors.lastname: Shaker
mesh_terms: D000818:Animals; D001676:Biofeedback, Psychology / Q000502:physiology; D015415:Biomarkers / Q000032:analysis; D002415:Cats; D003679:Deglutition / Q000502:physiology*; D004947:Esophagus / Q000502:physiology; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D008526:Medulla Oblongata / Q000166:cytology* / Q000502:physiology*; D009046:Motor Neurons / Q000166:cytology / Q000502:physiology; D010614:Pharynx / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis; D017552:Solitary Nucleus / Q000166:cytology / Q000502:physiology
chemical_list: D015415:Biomarkers; D016760:Proto-Oncogene Proteins c-fos