title: Pressor and depressor actions of prostanoids in the intact human fetoplacental vascular bed.
abstract: Effects of the prostanoids PGE2, PGF2 alpha, PGI2, PGE1, 6-keto-PGE1 and the PGH2 analogue U46619, on fetoplacental perfusion pressure were measured in human term placental cotyledons in which both fetal and maternal circuits were perfused at constant flow. Fetal arterial injections of bolus doses of PGE2, PGF2 alpha and U46619 caused reversible increases in fetal perfusion pressure. Pressor responses to PGF2 alpha and U46619 were dose-related, with threshold doses of less than or equal to 2 nmoles and 14 pmoles, respectively. Reversible dose-related decreases in fetoplacental perfusion pressure were elicited by fetal arterial injection of PGI2, 6-keto-PGE1 and PGE1; threshold concentrations were: PGI2 less than or equal to 10 pmoles, PGE1 less than or equal to 141 pmoles and 6-keto-PGE1 less than or equal to 270 pmoles. The potent depressor effect of PGI2 and the potent pressor effect of U46619, a TxA2 mimetic, in the intact human fetoplacental vascular bed suggest that endogenous PGI2 and TxA2 could play a role in modulating fetoplacental blood flow in the term placenta.
mesh_terms: D000527:Alprostadil / Q000031:analogs & derivatives / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D015237:Dinoprost; D011464:Epoprostenol / Q000494:pharmacology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D010477:Perfusion; D010920:Placenta / Q000098:blood supply* / Q000187:drug effects; D011247:Pregnancy; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology; D011453:Prostaglandins / Q000494:pharmacology*; D011458:Prostaglandins E / Q000494:pharmacology; D011460:Prostaglandins F / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
chemical_list: D011450:Prostaglandin Endoperoxides, Synthetic; D011453:Prostaglandins; D011458:Prostaglandins E; D011460:Prostaglandins F; C022950:6-ketoprostaglandin E1; D015237:Dinoprost; D011464:Epoprostenol; D000527:Alprostadil