Actions of vasoactive drugs on human placental vascular smooth muscle

Gen Pharmacol. 1990;21(5):719-27. doi: 10.1016/0306-3623(90)91024-l.


1. The effect of different vasoactive agents on segments of human chorionic arteries and veins was analyzed. 2. The order of these agents to produce maximal contractile responses was: 5-hydroxytryptamine (5-HT) = histamine (H) = K+ greater than noradrenaline (NA) greater than or equal to phenylephrine (PHEN) greater than clonidine (CLON), and with regard to their potencies (EC50 values) was: 5-HT greater than or equal to NA greater than or equal to H greater than PHEN greater than CLON greater than K+. Dopamine and isoproterenol did not elicit any type of response. 3. The receptors involved on the contractions elicited by agonists were analyzed. 4. The results obtained suggest that: (1) 5-HT is the most potent vasoconstrictor agent of all those tested, whose effects appear to be mediated by 5-HT2- but not by alpha 1-adrenergic receptors; (2) chorionic vessels also possess H1-receptors; and (3) ketanserin has more affinity to block 5-HT2-receptors than to block alpha 1-adrenergic- and H1-receptors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arteries / drug effects
  • Clonidine / pharmacology
  • Diphenhydramine / pharmacology
  • Dopamine / pharmacology
  • Female
  • Histamine / pharmacology
  • Humans
  • In Vitro Techniques
  • Muscle Tonus / drug effects
  • Muscle, Smooth, Vascular / drug effects*
  • Norepinephrine / pharmacology
  • Phenylephrine / pharmacology
  • Placenta / blood supply*
  • Pregnancy
  • Regional Blood Flow / drug effects
  • Serotonin / pharmacology
  • Veins / drug effects


  • Phenylephrine
  • Serotonin
  • Histamine
  • Diphenhydramine
  • Clonidine
  • Dopamine
  • Norepinephrine