Figure 1.
Response of the fetal and newborn ductus arteriosus to acute (COX-In d19) and chronic (COX-In d15–19) COX inhibition in vivo. DA=ductus and AO=transverse aorta lumen diameters. Acute COX inhibition constricted the fetal ductus at term gestation (n = 17 fetuses; 7 litters) compared with Control fetuses (n = 9; 6 litters). Chronic COX inhibition (n = 17; 6 litters) did not constrict the fetal ductus. Ductus closure in 4 hour-old newborn pups (chronically exposed to COX inhibitors in utero (n = 26; 11 litters) was significantly reduced (resulting in a PDA) compared to Control newborns (n = 12; 4 litters). *p<0.05 compared to fetal controls; § p<0.05 compared to newborn control.