title: Antioxidant effect of muscle relaxants (vecuronium, rocuronium) on the rabbit abdominal aortic endothelial damage induced by reactive oxygen species.
abstract: BACKGROUND
  Muscle relaxants induce vascular smooth muscle relaxation by inducing synthesis of the prostaglandins that influence vasomotor tone. However, the effects of muscle relaxants on endothelial cells and tissues following injury by reactive oxygen species (ROS) are unclear. We tested the effects of the muscle relaxants vecuronium and rocuronium on impaired acetylcholine (ACh)-induced relaxation following induction of ROS in rabbit aorta in vitro.
  
  
  METHODS
  Isolated rabbit abdominal aortic ring segments were pretreated with vecuronium or rocuronium at 10(-4), 3 × 10(-4), 10(-3) or 3 × 10(-3) M, with or without inhibitors of Cu/Zn superoxide dismutase (diethyldithiocarbamate; DETCA, 0.8 mM) or catalase (3-amino-1,2,4-triazole; 3AT, 50 mM). All groups of aortic rings were then exposed to ROS generated by electrolysis in the organ bath medium (Krebs-Henseleit solution). The effects of vecuronium and rocuronium on ROS-induced impairment of relaxation induced by ACh (10(-6) M) were assessed.
  
  
  RESULTS
  Aortic rings treated with vecuronium or rocuronium at 10(-4), 3 × 10(-4), 10(-3) or 3 × 10(-3) M preserved the capacity for ACh-induced endothelial relaxation following ROS exposure in a dose-dependent manner. Pretreatment with DETCA partially inhibited the protective effects of vecuronium and rocuronium on ACh-induced relaxation (P < 0.001), but pretreatment with 3AT had no effect.
  
  
  CONCLUSIONS
  Muscle relaxants protected the endothelium in isolated rabbit abdominal aorta from free-radical injury in a dose-dependent manner. These results suggest that vecuronium and rocuronium may act as superoxide anion scavengers.
authors.affiliation: Department of Anesthesilogy and Pain Medicine, School of Medicine, Hanyang University, Seoul, Korea.
authors.forename: Ji Seon
authors.initials: JS
authors.lastname: Jeong
authors.affiliation: Department of Anesthesilogy and Pain Medicine, School of Medicine, Hanyang University, Seoul, Korea.
authors.forename: Jung Kook
authors.initials: JK
authors.lastname: Suh
authors.affiliation: Department of Anesthesilogy and Pain Medicine, School of Medicine, Hanyang University, Seoul, Korea.
authors.forename: Eun Sun
authors.initials: ES
authors.lastname: Cho
authors.affiliation: Department of Anesthesilogy and Pain Medicine, School of Medicine, Hanyang University, Seoul, Korea.
authors.forename: Dong Won
authors.initials: DW
authors.lastname: Kim
authors.affiliation: Department of Anesthesilogy and Pain Medicine, School of Medicine, Hanyang University, Seoul, Korea.
authors.forename: Mi Ae
authors.initials: MA
authors.lastname: Jeong
keywords: Antioxidant effect; Reactive oxygen species; Rocuronium; Vecuronium