Ductus arteriosus is maintained open due to -
Ans. is 'b' i.e., Prostaglandins Prostaglandins and ductus arteriosuso The E series of prostaglandins are responsible for maintaining the patency of the DA (by dilation of vascular smooth muscle) throughout the fetal period.o Prostaglandin E2 (PGE2), produced by both the placenta and the DA itself, is the most potent of the E prostaglandins, but prostaglandin El (PGE1) also has a role in keeping the DA open. PGE1 and PGE2 keep the DA open via involvement of specific PGE-sensitive receptors (such as EP2 or EP4).o EP4 is the major receptor associated with PGE2-induced dilation of the DA and can be found across the DA in smooth muscle cells.o Immediately after birth, the levels of both PGE2 and the EP4 receptors reduce significantly, allowing for closure of the DA and establishment of normal postnatal circulation.Ductus arteriosuso Ductus arteriosus is a shunt between pulmonary trunk and desending Aorta.o Functional closure of ductus occurs within 15 hours after birth. Increasing oxygen saturation causes the muscle of ductus to constrict -In full term neonates the ductus arteriosus closes within 10 to 25 days (Anatomic closure)Management of PDAo NSAIDs (most commonly indomethacin) are used to induce closure of PDA, as these drugs inhibit synthesis of prostaglandins (Prostaglanding are involved in maintainance of patency of ductus arteriosuso If indomethacin is not successful and the ductus remains hemodynamically significant, surgical ligation with or without division of ductus should be performed.
Decreased oxygen to fetal heart
Prostaglandins
ATP
Lack of respiratory effort
C.V.S.