title: [Effects of restraint position on changes of diaphragmatic mechanical characteristic in rats].
abstract: OBJECTIVE
  To observe effects of restraint position on the changes of diaphragmatic mechanical characteristic in rats, and try to explore the role of nitric oxide (NO).
  
  
  METHODS
  Rat model of restraint position was established. Rats were divided into control group, restraint position 12h and 24h groups. The markers of respiratory functions in vivo and the biomechanical markers of diaphragmatic characteristic ex vivo were evaluated. Serum NO levels were measured with spectrophotometry. The expressions of nNOS and iNOS mRNA in diaphragm were detected using RT-PCR.
  
  
  RESULTS
  Compared with control group, respiratory rate, tidal volume and minute ventilation were significantly decreased in the restraint position 12h and 24h groups. Pt of diaphragm significantly decreased and force-generating capacity reduced at low frequency stimulation in 12h group. Force-generating capacity over the full range reduced at low and high frequency stimulation in 24h group. Pt of diaphragm in control and restraint position groups increased after L-NNA pre-incubation. Force-frequency relationship after L-NNA pre-incubation reduced in 24h group. NO level in serum increased significantly in the restraint position groups. Diaphragmatic nNOS mRNA expression was upregulated significantly in the restraint position groups.
  
  
  CONCLUSIONS
  Restraint position induces the decreasement of diaphragmatic contractility and the decreasement is mediated by NO from diaphragm or circulation blood.
authors.affiliation: Department of Forensic Medicine, Medical School of Nantong University, Nantong 226001, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Xiang
authors.forename: Su-Dong
authors.initials: SD
authors.lastname: Guan
authors.forename: Jun
authors.initials: J
authors.lastname: Yan
authors.forename: Hui-Yun
authors.initials: HY
authors.lastname: Wang
authors.forename: Xin-Hai
authors.initials: XH
authors.lastname: Cen
authors.forename: Xiang-He
authors.initials: XH
authors.lastname: Song
authors.forename: Shou-Gong
authors.initials: SG
authors.lastname: Chen
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Zhen-Yong
authors.initials: ZY
authors.lastname: Gu
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D003964:Diaphragm / Q000378:metabolism / Q000502:physiology / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D009129:Muscle Tonus / Q000502:physiology; D009569:Nitric Oxide / Q000097:blood* / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism; D011187:Posture; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012120:Respiration Disorders / Q000209:etiology / Q000503:physiopathology; D012149:Restraint, Physical; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D012333:RNA, Messenger; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase