title: [Effect of apelin on vasodilatation of isolated pulmonary arteries in rats is concerned with the nitric oxide pathway].
abstract: OBJECTIVE
  To investigate the effect of apelin on vasodilatation of isolated pulmonary arterial rings in rats and its relationship to the nitric oxide (NO) pathway, and to observe the difference of vasodilatation between hypoxic rats and normoxic rats.
  
  
  METHODS
  Thirty-six male Sprague-Dawley (SD) rats were randomly divided into hypoxic group and normoxic group. The effects of accumulated apelin on pulmonary arterial rings preconstricted with norepinephrine (NE) were observed by using tissue organ bath system. After pulmonary arterial rings were pretreated with three methods: removing the endothelium, pretreating with nitric oxide synthase inhibitor L-NAME or soluble guanylatecyclase inhibitor ODQ, the different effect of apelin was observed. In addition, the difference of vasodilatation between hypoxic rats and normal rats were observed.
  
  
  RESULTS
  (1) Exposure of intact endothelium pulmonary arterial rings preconstricted by NE to apelin at concentration (0.01 - 100 nmol/L) induced a significant concentration dependent relaxation. The maximal vasorelaxant effect of apelin was 10.62% +/- 2.60%, which was inhibited by removal of the endothelium (P < 0.01), pretreatment with L-NAME (P < 0.01) or ODQ (P < 0.01). (2) Response of pulmonary arterial rings from hypoxic pulmonary hypertension rats was decreased (P < 0.05). Compared to normal rats, at a concentration of 100 nmol/L, the response to apelin on arteries from hypoxic rats decreased 60.45% (P < 0.01). But the values of EC50 were not significantly different (P > 0.05).
  
  
  CONCLUSIONS
  These results indicate that apelin relaxes the pulmonary arterial rings of rats in an endothelium dependent manner, which may have a relationship to NO signaling pathway. The response of vasodilatation is decreased in the pulmonary arterial rings from the hypoxic rats.
authors.affiliation: Laboratory of Cor Pulmonale, Institute of Hypoxia Medicine, Wenzhou Medical College, Wenzhou 325035, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Huang
authors.forename: Xiao-Fang
authors.initials: XF
authors.lastname: Fan
authors.forename: Ling-Xia
authors.initials: LX
authors.lastname: Pan
authors.forename: Yu-Qi
authors.initials: YQ
authors.lastname: Gao
authors.forename: Sun-Zhong
authors.initials: SZ
authors.lastname: Mao
authors.forename: Liang-Gang
authors.initials: LG
authors.lastname: Hu
authors.forename: Lin
authors.initials: L
authors.lastname: Hong
authors.forename: Ran
authors.initials: R
authors.lastname: Chen
authors.forename: Yong-Sheng
authors.initials: YS
authors.lastname: Gong
mesh_terms: D000818:Animals; D000073861:Apelin; D000860:Hypoxia / Q000503:physiopathology*; D066298:In Vitro Techniques; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology*; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D011651:Pulmonary Artery / Q000503:physiopathology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D000073861:Apelin; C498579:Apln protein, rat; D036341:Intercellular Signaling Peptides and Proteins; D009569:Nitric Oxide