title: Vasorelaxant effect of opioid analgesics on the isolated human radial artery.
abstract: OBJECTIVE
  Arterial grafts are prone to vasospasm. Opioid analgesics are commonly used in the perioperative course of cardiac surgical procedures. Therefore, we investigated the direct effects of morphine, meperidine, fentanyl and remifentanil on the human radial artery.
  
  
  METHODS
  Radial artery segments, obtained from 20 patients, were precontracted with phenylephrine. Using the organ bath technique, the endothelium-independent vasodilatation was tested in vitro by addition of cumulative concentrations of morphine, meperidine, fentanyl and remifentanil in separate organ baths, in the presence or absence of naloxone. Indomethacin and NG-nitro-L-arginine methyl ester was added to all organ bath in order to determine the effects of prostaglandins and nitric oxide, respectively.
  
  
  RESULTS
  Morphine (10(-8) - 10(-4) mol L-1), meperidine (10(-10) - 10(-6) mol L-1), fentanyl (10(-10) - 10(-6) mol L-1) and remifentanil (10(-8) - 10(-4) mol L-1) caused a concentration-dependent vasorelaxation in the human being artery rings. The relaxations in the presence of naloxane did not change. The maximal relaxant effects of meperidine and fentanyl were significantly greater than those of morphine and remifentanil (P < 0.05).
  
  
  CONCLUSIONS
  These findings indicate that morphine, meperidine, fentanyl and remifentanil produce concentration-dependent and endothelium-independent relaxations in human being radial artery rings. Meperidine and fentanyl are more potent relaxant agents than morphine and remifentanil in the human being radial artery in vitro.
authors.affiliation: Department of Anesthesiology, Cumhuriyet University School of Medicine, Sivas, Turkey. sgursoy@cumhuriyet.edu.tr
authors.forename: S
authors.initials: S
authors.lastname: Gursoy
authors.forename: I
authors.initials: I
authors.lastname: Bagcivan
authors.forename: M K
authors.initials: MK
authors.lastname: Yildirim
authors.forename: O
authors.initials: O
authors.lastname: Berkan
authors.forename: T
authors.initials: T
authors.lastname: Kaya
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000704:Analysis of Variance; D004305:Dose-Response Relationship, Drug; D005260:Female; D005283:Fentanyl / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008614:Meperidine / Q000494:pharmacology; D008875:Middle Aged; D009020:Morphine / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D017534:Radial Artery / Q000187:drug effects*; D000077208:Remifentanil; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D000701:Analgesics, Opioid; D010880:Piperidines; D009020:Morphine; D008614:Meperidine; D000077208:Remifentanil; D005283:Fentanyl