title: Effects of polyamines on human umbilical artery tone in vitro.
abstract: OBJECTIVE
  Polyamines act as endogenous modulators of cell function and excitability. There are no data in relation to their effects on the human fetoplacental circulation. The aim of this study was to investigate the effects of the polyamines, spermine, and spermidine on human umbilical artery resistance in vitro.
  
  
  METHODS
  Isometric tension recordings were performed under physiologic conditions on human umbilical arterial rings (n = 12). The in vitro effects of spermine and spermidine (at concentrations ranging between 10(-9) M to 10(-3) M) were measured, and compared with those measured in vehicle control experiments. The maximal inhibition (MMI) at the highest concentration and the pD2 (-log EC50) values for each compound were calculated and compared.
  
  
  RESULTS
  Spermine and spermidine exerted a potent relaxant effect on human umbilical arterial tone in comparison to vehicle control experiments. The MMI +/- SEM for spermine was 18.41 +/- 1.437% (n = 6; P <.001) and for spermidine was 38.31 +/- 3.572% (n = 6; P <.001). There was no difference observed between the pD2 +/- SEM values for spermine (5.78 +/- 1.54; n = 6) and spermidine (6.27 +/-0.85; n = 6) (P = .517).
  
  
  CONCLUSIONS
  The polyamines spermine and spermidine exert a potent relaxant effect on human umbilical artery tone suggestive of an endogenous role for these compounds in vasomotor regulation of the fetoplacental circulation.
authors.affiliation: Department of Obstetrics and Gynaecology, Clinical Science Institute, National University of Ireland Galway, University College Hospital, Galway, Ireland.
authors.forename: Nandini
authors.initials: N
authors.lastname: Ravikumar
authors.forename: Diarmaid D
authors.initials: DD
authors.lastname: Houlihan
authors.forename: John J
authors.initials: JJ
authors.lastname: Morrison
mesh_terms: D000328:Adult; D005260:Female; D005865:Gestational Age; D006801:Humans; D066298:In Vitro Techniques; D011073:Polyamines / Q000494:pharmacology*; D011247:Pregnancy; D013095:Spermidine / Q000494:pharmacology; D013096:Spermine / Q000494:pharmacology; D014469:Umbilical Arteries / Q000187:drug effects* / Q000502:physiology*; D014664:Vasodilation / Q000187:drug effects
chemical_list: D011073:Polyamines; D013096:Spermine; D013095:Spermidine