Differential responses of human fetal umbilical vasculatures to oxytocin and epinephrine

ABSTRACT

The effects of syntocinon [synthetic oxytocin] and epinephrine on isolated segments of human fetal umbilical arteries and veins were investigated. A ten umbilical cords delivered after normal vaginal delivery were used, their arteries and veins were dissected and prepared. The results showed that the administration of adrenaline in various dosed [2, 4, 8 ug/ml] resulted in an immediate prolonged significant increase in the tension developed [T. max] of both umbilical arteries and veins. However, the administration of syntocinon [1, 2, 4 IU/ml] induced two differential responses, i.e a vascorelaxant and a venoconstrictor response on fetal umbilical arteries and veins respectively. These responses were found to be a dose dependent. In addition, it was observed that the vasorelaxant effect of oxytocin on the umbilical arteries was preserved even after the administration of high pressor dose of epinephrine [8 ug/ml]