EP14.26: Ketanserin can reduce vascular resistance in umbilical and placental veins but not in arteries both in IUGR and control pregnancies

Abstract

Our aim was to test the vasoreactivity to serotonin, a humoral factor that is present measurably. To get more detailed information we added ketanserin, a selective 5-HT2 receptor antagonist. Patients were enrolled in case and control groups based on third trimester EFW. The placenta and umbilical cord was immediately placed and stored in Krebs-Henseleit solution until the experiment (max. 24 hours). After incubation, cumulative serotonin dosage (10-9-10-5M) was added to the vessels with or without 10-8M ketanserin. The 3DPD indices were VI=4.5 in IUGR and 10.1 in controls (p<0.001), the FI=38.5 (p<0.05) and 49.2, and the VFI=2.7 and 4.9 (p<0.01) respectively. Reactivity to serotonin considering the end point of each dose is presented in table 1. The contraction of IUGR umbilical arteries was the most powerful (p=0.03) that strongly correlated with a. umbilicalis S/D (r= 0,80, R2: 0,63). From the AUC values, the maximum effects (Emax) and its 50% (EC50) of serotonine were calculated, In umbilical veins EC50, in placental veins EC50 and Emax showed difference (p<0,05) between IUGR and controls. According to our preliminary results incubation with ketanserin did alter the maximal response in umbilical veins in both groups (p<0.05) but did not affect that in arteries. Difference of endpoint and AUC analysis depends on how fast contraction reaches its peak. In arteries ketanserin did not alter the vascular reactivity, other 5-HT receptors may dominate the regulation and in veins 5-HT2 receptor may be present more densely and can participate in reducing vascular resistance. EP14.26: Table 1. Serotonin concentration that elicits significant contraction