Effects of serotonin on vascular tone of isolated human placental chorionic veins.
Vasomotor effects of serotonin (5-hydroxytryptamine; 5-HT) were studied in isolated human placental chorionic veins in vitro. 5-HT produced marked contraction with a maximum of 89 +/- 5.05% of the K(+)-induced contractions. This response was specifically and competitively antagonized by ketanserin at doses of 10(-9) and 10(-8) M (pA2 = 9.65). Ketanserin, at concentrations up to 10(-7) M, induced noncompetitive inhibition of the contractions. These findings show a marked vasoconstrictor effect of 5-HT on the capacitance vessels of the human placenta, which suggests that this amine could play an important role as a mediator of fetal circulation. The possible therapeutic effect of ketanserin as a vasodilator to improve blood flow in the uteroplacental unit, is also discussed, based on the ability of this drug to block competitively 5-HT effects on chorionic veins.
Gonzalez
C
C
Departamento de Ciencias Fisiológicas, Facultad de Ciencias Biológicas y de Recursos Naturales, Universidad de Concepción, Chile.
Cruz
M A
MA
Sepulveda
W H
WH
Rudolph
M I
MI
D002823:Chorion / Q000098:blood supply*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D066298:In Vitro Techniques; D007650:Ketanserin / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects*
D012701:Serotonin; D007650:Ketanserin