Background: To investigate the vascular resistance and the vasoactive effects of serotonin in arteries from single umbilical artery (SUA) cords.
Methods: The preparations were sampled from 10 patients with SUA cords. The control group (n=20) was matched according to gestational age, birth weight percentile, blood pressure and proteinuria. The arterial segments were perfused in vitro employing a constant perfusion rate and measuring alterations in perfusion pressure. Following an initial test with serotonin 10(-7) M the drug was administrated in stepwise increasing concentrations from 10(-10) to 10(-5) M.
Results: The vascular resistance was significantly reduced in the SUA group compared to the control group (p<0.01). In about half of the preparations in both groups serotonin 10(-7) M induced a transient pressure decrease followed by a larger pressure increase. The remaining arteries showed a monophasic pressure increase. The maximum constrictory response calculated in percent of the prestimulatory perfusion pressure was significantly increased (p<0.01) in the SUA compared to the control group, but non-significantly increased (p=0.073) when calculated in absolute values (mmHg).
Conclusions: Arteries in SUA cords display reduced vascular resistance compared to arteries from normal cords in in vitro perfused preparations. The response pattern to serotonin was not altered, but the constrictory response might be increased in arteries from SUA cords.