Doppler Flow Velocity Waveforms and Vasoactive Effects of Serotonin in Human Umbilical Arteries

Abstract

The vasoactive effect of serotonin was investigated by in vitro perfusion in human umbilical arteries in which antenatal Doppler ultrasound examination revealed abnormal velocity waveforms. The results were compared to those obtained in preparations from normotensive uncomplicated term pregnancies as well as from preterm deliveries in which antenatal Doppler ultrasound examination showed normal velocity waveforms related to gestational age. Serotonin induced a monophasic vasoconstriction or a biphasic pressure response with a transient pressure decrease succeeded by a constrictory response. In all groups serotonin induced a significant (p < 0.001) constrictory response, whereas no significant differences were observed between the groups. At a serotonin dose of 10^–7 mol/l, the frequency of preparations with a biphasic pressure response was significantly smaller in the preparations with abnormal diastolic flow as compared to the term control group (5/18 vs. 13/19, p = 0.02), but not significantly different from that of the preterm control group (3/9). The umbilical arterial responsiveness to serotonin does not seem to be dependent on antenatal Doppler velocity waveforms.