title: Adjunct nitrous oxide normalizes vascular reactivity changes after hemorrhagic shock in mice under isoflurane anesthesia.
abstract: BACKGROUND
  Hemorrhagic shock is associated with changes in vascular responsiveness that may lead to organ dysfunction and, ultimately, multiple organ dysfunction syndrome. Volatile anesthetics interfere with vasoresponsiveness, which may contribute to organ hypoperfusion. In this study, the authors examined the influence of adjunct nitrous oxide on the vascular responsiveness after short-term hemorrhagic shock under isoflurane anesthesia.
  
  
  METHODS
  Spontaneously breathing mice (n = 31, 27.6 +/- 0.31 g) were anesthetized with isoflurane (1.4%) or with isoflurane (1.4%) and adjunct nitrous oxide (66%). Both groups were divided into Sham, Shock, and Resuscitated groups. Vascular reactivity to phenylephrine and acetylcholine and expression of cyclooxygenases were studied in the aorta.
  
  
  RESULTS
  In the isoflurane-anesthetized groups, the contractile response to phenylephrine was increased in the Shock as compared with the Sham and Resuscitated groups (Emax = 3.2 +/- 0.4, 1.2 +/- 0.4, and 2.5 +/- 0.5 mN, respectively). Adjunct nitrous oxide increased phenylephrine contraction to a similar level in all three groups. In the Sham isoflurane group, acetylcholine caused a biphasic response: An initial relaxation followed by a contractile response sensitive to cyclooxygenases inhibition by indomethacine. The contractile response was abrogated in the isoflurane-anesthetized groups that underwent shock. In all groups, adjunct nitrous oxide preserved the contractile phase. Shock induced a down-regulation of cyclooxygenases-1, which was normalized by adjunct nitrous oxide.
  
  
  CONCLUSIONS
  Adjunct nitrous oxide attenuates shock-induced changes in vascular reactivity and cyclooxygenases expression of mice under isoflurane anesthesia. This implies that vascular reactive properties during anesthesia in hemorrhagic shock conditions may be influenced by the choice of anesthetics.
authors: Department of Clinical Pharmacology, University Medical Center Groningen, University of Groningen, The Netherlands. i.v.samarska@med.umcg.nl
authors: Iryna V
authors: IV
authors: Samarska
authors: Matijs
authors: M
authors: van Meurs
authors: Hendrik
authors: H
authors: Buikema
authors: Martin C
authors: MC
authors: Houwertjes
authors: Francis M
authors: FM
authors: Wulfert
authors: Grietje
authors: G
authors: Molema
authors: Anne H
authors: AH
authors: Epema
authors: Robert H
authors: RH
authors: Henning
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation / Q000627:therapeutic use*; D000818:Animals; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000502:physiology; D001808:Blood Vessels / Q000187:drug effects* / Q000503:physiopathology*; D015153:Blotting, Western; D051545:Cyclooxygenase 1 / Q000096:biosynthesis; D051546:Cyclooxygenase 2 / Q000096:biosynthesis; D007530:Isoflurane; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D009609:Nitrous Oxide / Q000627:therapeutic use*; D012771:Shock, Hemorrhagic / Q000188:drug therapy* / Q000503:physiopathology*; D014661:Vasoconstriction / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D018685:Anesthetics, Inhalation; D020030:Nitric Oxide Donors; D014665:Vasodilator Agents; D009599:Nitroprusside; D007530:Isoflurane; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D009609:Nitrous Oxide; D000109:Acetylcholine