8429 Serotonin Receptor Antagonist Alleviates Vascular Defects Produced by Selective Serotonin Reuptake Inhibitor Treatment During Gestation

Abstract Disclosure: L.P. Agnew: None. R. Domingues: None. A. Weichmann: None. L.L. Hernandez: None. Maternal mental health is critical for both mother and infant and often antidepressant therapy outweighs the potential risks of selective serotonin reuptake inhibitor (SSRI) treatment; however, SSRI use is associated with adverse neonatal outcomes. Preliminary work in our laboratory revealed placental apoptosis in pregnant dams treated with fluoxetine (FLX) and dams genetically deficient for the serotonin transporter gene. We hypothesize that SSRIs decrease placental blood flow, causing apoptosis and organ death via signaling through the serotonin 2A/2C receptors. Pregnant female C57BL6 mice were randomized to be treated daily, via I.P. injection, from E10-17.5 with saline (CON; n=6), 2 mg/kg FLX (n=5), or 2 mg/kg ketanserin plus 2 mg/kg FLX (n=5). On E17.5, using high-resolution ultrasound imaging, we identified the uterine artery, individual umbilical cords, and placental disc blood vessels. We calculated blood pressure, blood volume, blood flow rate, and heart rate in the uterine artery, umbilical cord, and placental disc. FLX (decreased blood volume in the uterine artery compared to ketanserin plus FLX (48.42 ± 18.26, 116.54 ± 45.25; p=0.0077), and decreased average (89.38 ± 31.50) and peak (130.36 ± 39.05) blood velocity in the uterine artery compared to ketanserin plus FLX average (162.76 ± 68.46; p=0.0322) and peak (236.77 ± 92.43; p=0.0242) blood velocity. FLX decreased average (0.04 + 0.02) and peak (0.07 ± 0.04) blood pressure in the uterine artery compared to ketanserin and FLX treated animals average (0.12 ± 0.10; p=0.0634) and peak (0.25 ± 0.19; p=0.0412) blood pressure. Ketanserin plus FLX (391 ± 38.29) decreased heart rate (BPM) in the placental disc compared to untreated controls (450.67 ± 26.08; p=0.0128). In the umbilical cord, ketanserin plus FLX (393 ± 28.25) decreased BPM compared to CON (450.17 ± 29.44; p=0.0078) and compared to FLX treatment alone (437.20 ± 17.28; p=0.0450). FLX treatment of dams during pregnancy reduces blood flow volume, heart rate, and blood flow velocity to the placenta via the uterine artery. The use of ketanserin, an inhibitor of serotonin receptor 2A/2C signaling, in combination with FLX, reduced the effects of FLX on the uterine artery. These data suggest that treatment with ketanserin could be utilized to alleviate the reproductive side effects of antidepressant usage for pregnant mothers while allowing the mother to remain on antidepressants. Future research should further investigate the effects of SSRI and ketanserin on blood flow to the fetus through the umbilical cord. Presentation: 6/2/2024