title: [Dexmedetomidine inhibits 5-HT-induced intrapulmonary artery vasoconstriction].
abstract: OBJECTIVE
  To investigate the effect of dexmedetomidine on 5-HT-induced constrictions of isolated human intrapulmonary arteries and explore the mechanisms.
  
  
  METHODS
  Lung tissue was obtained from patients undergoing surgery for lung carcinoma. Intrapulmonary arteries were dissected and cut into rings, which were mounted in a Multi Myograph system to determine the effect of dexmedetomidine (0.3-3 nmol/L) on 5-HT-induced vasoconstrictions. The influences of the endothelium removal and various drugs including L-NAME, yohimbine and indomethacin were tested on the effects of dexmedetomidine.
  
  
  RESULTS
  Dexmedetomidine (0.1-100 nmol/L) did not obviously affect the resting tension of endothelium-intact human intrapulmonary arteries. 5-HT induced concentration-dependent contraction in endothelium-intact intrapulmonary arteries [pD2: 6.11∓0.05, Emax: (102.10∓1.96)%]. In the rings with intact endothelium, dexmedetomidine (0.3-3 nmol/L) significantly attenuated the Emax and pD2 of 5-HT-induced vasoconstriction [pD2: 5.94∓0.03, Emax: (79.96∓1.31)%]. 5-HT also induced concentration-dependent contraction in endothelium-denuded intrapulmonary arteries [pD2: 6.10∓0.07, Emax: (107.40∓3.20)%]. Dexmedetomidine produced no significant effects on the rings with denuded endothelium. The effects of dexmedetomidine on 5-HT-induced vasoconstriction was suppressed by L-NAME and yohimbine, but not by indomethacin.
  
  
  CONCLUSIONS
  Dexmedetomidine can inhibit 5-HT-induced vasoconstriction of isolated human intrapulmonary arteries probably through α2-adrenergic acceptor and NO released from the endothelium.
authors.affiliation: 1Southern Medical University, Guangzhou 510515, China; 3Department of Anesthesiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, Guangzhou 510080, China. E-mail: nonglidan@sina.com.
authors.forename: Lidan
authors.initials: L
authors.lastname: Nong
authors.forename: Chunyu
authors.initials: C
authors.lastname: Deng
authors.forename: Sujuan
authors.initials: S
authors.lastname: Kuang
authors.forename: Guangyan
authors.initials: G
authors.lastname: Zhang
authors.forename: Jianxiu
authors.initials: J
authors.lastname: Cui
mesh_terms: D000328:Adult; D000368:Aged; D020927:Dexmedetomidine / Q000494:pharmacology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D012701:Serotonin; D020927:Dexmedetomidine