VENOUS PLACENTAL REACTIVITY TO SEROTONIN IN NORMAL AND PREECLAMPTIC GESTANTS

The effect of serotonin (5-HT) on the contractile activity of venous chorionic rings from normal and preeclamptic gestants was analyzed. The results indicate that the resting tension did not differ between the groups, but the spontaneous rhythmic contractions began earlier and were of higher amplitude in the preeclamptic group. Dose-response data indicate that venous segments from preeclamptic patients developed a 1.7-fold increase in sensitivity to 5-HT. These effects were accompanied by an increase in maximal isometric tension (E(max)) and relaxation times. Decreased desensitization and lack of tachyphylaxis was observed in most of the vascular preparations from the preeclamptic group. These data suggest that 5-HT may have a role in the modulation of preeclampsia.