title: Temporary forced oral breathing affects neonates oxygen consumption, carbon dioxide elimination, diaphragm muscles structure and physiological parameters.
abstract: OBJECTIVE
  We studied adaptation of diaphragm, oxygen consumption and carbon dioxide elimination to forced oral breathing (lasting for only 4 days) following reversible bilateral nasal obstruction performed on day 8 post-natal male rats.
  
  
  METHODS
  Diaphragm myosin heavy chain (MHC) composition, oxygen consumption, carbon dioxide elimination and hormones level were analysed during nasal obstruction period.
  
  
  RESULTS
  Diaphragm muscle showed significant increases in adult isoforms (MHC 1, 2a) in oral breathing group versus control. Reversible nasal obstruction was associated with a decrease of oxygen consumption and carbon dioxide elimination. Nasal obstruction period was associated with reduced growth of the olfactory bulbs and an initial decrease in lung growth. One day after implementing nasal obstruction, basal corticosterone levels had increased (by over 1000). Oral breathing was also associated with a lower level of thyroid hormone.
  
  
  CONCLUSIONS
  We conclude that a 4 day nasal obstruction period in young rats leads to hormonal changes and to Diaphragm myosin heavy chain structural adaptation.
authors.affiliation: Université des Sciences et Techniques de Masuku, BP: 943 Franceville, Gabon; Université de Lorraine, 34 cours Léopold 54000 Nancy, France. Electronic address: padzys@yahoo.fr.
authors.forename: Guy Stéphane
authors.initials: GS
authors.lastname: Padzys
authors.affiliation: Université des Sciences et Techniques de Masuku, BP: 943 Franceville, Gabon.
authors.forename: Linda Priscillia
authors.initials: LP
authors.lastname: Omouendze
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D000831:Animals, Newborn; D002245:Carbon Dioxide / Q000378:metabolism*; D003345:Corticosterone / Q000097:blood; D003964:Diaphragm / Q000378:metabolism* / Q000502:physiology; D004586:Electrophoresis; D009058:Mouth Breathing / Q000503:physiopathology*; D018995:Myosin Heavy Chains / Q000378:metabolism*; D015508:Nasal Obstruction; D010092:Oximetry; D010101:Oxygen Consumption / Q000502:physiology*; D020033:Protein Isoforms / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D020033:Protein Isoforms; D014284:Triiodothyronine; D002245:Carbon Dioxide; D018995:Myosin Heavy Chains; D013974:Thyroxine; D003345:Corticosterone
keywords: Carbon dioxide elimination; Myosin heavy chains; Nasal obstruction; Oral breathing; Oxygen consumption; Respiratory muscle