title: [Changes of reactivity of rabbit femoral venous rings after 21 d simulated weightlessness].
abstract: OBJECTIVE
  To study the effects of simulated weightlessness on reactivity of leg veins.
  
  
  METHODS
  Vascular bathing technique was used to measure the contractile responses of rabbit femoral venous rings to Ht, PE and KCl, and the dilatory responses to ACh and SNP after horizontal confinement or head-down tilt confinement for 21 d.
  
  
  RESULTS
  After simulated weightlessness for 21 d, the contractile response of rabbit femoral venous rings to higher concentrations of PE and KCl decreased significantly (P<0.05); the contractile response to Ht also decreased, but not significantly (P>0.05); the dilatory responses to ACh and SNP did not change significantly in both groups.
  
  
  CONCLUSIONS
  Contractile response of rabbit femoral vein decreased after simulated weightlessness for 21 d, which might partly explain the occurrence of orthostatic intolerance in men after space flight.
authors.affiliation: Institute of Space Medico-engineering, Beijing, China.
authors.forename: Wen-bin
authors.initials: WB
authors.lastname: Liang
authors.forename: Shi-zhong
authors.initials: SZ
authors.lastname: Jiang
authors.forename: Xian-yun
authors.initials: XY
authors.lastname: Shen
authors.forename: Jian-wen
authors.initials: JW
authors.lastname: Dong
authors.forename: Tie-min
authors.initials: TM
authors.lastname: Ma
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001835:Body Weight; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D005268:Femoral Vein / Q000187:drug effects / Q000502:physiology*; D010656:Phenylephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011817:Rabbits; D012701:Serotonin / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000494:pharmacology*; D014666:Vasomotor System / Q000187:drug effects / Q000502:physiology*; D018474:Weightlessness Simulation
chemical_list: D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D010656:Phenylephrine; D012701:Serotonin; D011189:Potassium Chloride; D000109:Acetylcholine