title: Spontaneous swallowing occurs during autoresuscitation in the in situ brainstem preparation of rat.
abstract: Previous studies report that upper airway reflexes are operational during autoresuscitation from respiratory arrest. We investigated swallowing/breathing interactions, measured by recording of vagal (VNA) and phrenic nerve activities (PNA), during autoresuscitation in the in situ perfused brainstem preparation of juvenile rats. During the initial surgery, respiratory arrest was induced by exsanguination and cooling. Reperfusion (i.e. re-oxygenation and re-warming) of the brainstem circuits was associated with frequent spontaneous swallowing before resumption of respiration (n=6, 'stage 1 autoresuscitation'). When recovered, the respiratory pattern was transiently apneustic-like ('stage 2 autoresuscitation'). Spontaneous swallowing often occurred at the end of the prolonged PNA (n=9/12). Successful autoresuscitation was characterised by re-establishment of the 3 phase respiratory motor pattern and no spontaneous swallowing. Pharmacological inhibition (isoguvacine, 10 mM, 50-75 nl; n=10) of the Kölliker-Fuse nucleus (KF) mimicked stage 2 autoresuscitation. However, the frequency of spontaneous swallowing after KF inhibition did not correlate with subsequent recovery of the eupneic respiratory motor pattern.
authors.affiliation: Florey Institute of Neuroscience and Mental Health, Gate 11, Royal Parade, University of Melbourne, Victoria 3010 Australia. Electronic address: tara.bautista@florey.edu.au.
authors.forename: Tara G
authors.initials: TG
authors.lastname: Bautista
authors.affiliation: Department of Physiology, University of Melbourne, Victoria 3010, Australia.
authors.forename: Angelina Y
authors.initials: AY
authors.lastname: Fong
authors.affiliation: Florey Institute of Neuroscience and Mental Health, Gate 11, Royal Parade, University of Melbourne, Victoria 3010 Australia.
authors.forename: Mathias
authors.initials: M
authors.lastname: Dutschmann
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D001933:Brain Stem / Q000187:drug effects / Q000502:physiology*; D003679:Deglutition / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D058734:Exsanguination / Q000139:chemically induced / Q000503:physiopathology; D018755:GABA Agonists / Q000494:pharmacology; D007539:Isonicotinic Acids / Q000494:pharmacology; D010791:Phrenic Nerve / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration / Q000276:immunology*; D012131:Respiratory Insufficiency / Q000209:etiology; D012137:Respiratory System; D014630:Vagus Nerve / Q000502:physiology
chemical_list: D018755:GABA Agonists; D007539:Isonicotinic Acids; C015300:isoguvacine
keywords: Autoresuscitation; Hypothermia; Hypoxia; Respiratory; Swallowing; Upper airway