title: Platelet aggregation inhibiting activity of human placental chorioepithelial brush border membrane vesicles.
abstract: We investigated the platelet aggregation inhibiting activity of human placental brush border membrane vesicles (BBMV) and obtained the following results. A strong platelet aggregation inhibiting activity existed in placental BBMV. The BBMV inhibited the platelet aggregation induced by ADP, arachidonic acid, collagen and ristocetin in a dose-dependent manner. The protein concentration of BBMV giving 50 per cent inhibition was 52 +/- 6 micrograms/ml for ADP-induced platelet aggregation, 21 +/- 2 micrograms/ml for arachidonic acid-induced platelet aggregation, 19 +/- 2 micrograms/ml for collagen-induced platelet aggregation and 107 +/- 9 micrograms/ml for ristocetin-induced platelet aggregation. There was a high level of ADP degrading activity (ADPase activity) in the placental BBMV. ADP degrading activity of the BBMV: 10.5 +/- 0.5 mumol/mg protein/min was 21 times greater than that of homogenate of the placental villi. The placental BBMV inhibited platelet TXA2 production. In the 40 micrograms/ml protein concentration of placental BBMV, platelet TXA2 production was almost completely inhibited.
authors.affiliation: Department of Obstetrics and Gynecology, Nara Medical University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Iioka
authors.forename: S
authors.initials: S
authors.lastname: Akada
authors.forename: T
authors.initials: T
authors.lastname: Shimamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Yamada
authors.forename: Y
authors.initials: Y
authors.lastname: Sakamoto
authors.forename: S I
authors.initials: SI
authors.lastname: Moriyama
authors.forename: M
authors.initials: M
authors.lastname: Ichijo
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism / Q000494:pharmacology; D016718:Arachidonic Acid / Q000494:pharmacology; D001792:Blood Platelets / Q000378:metabolism; D002824:Chorionic Villi / Q000502:physiology*; D003094:Collagen / Q000494:pharmacology; D011464:Epoprostenol / Q000096:biosynthesis; D005260:Female; D006801:Humans; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000502:physiology; D012310:Ristocetin / Q000494:pharmacology; D013928:Thromboxane A2 / Q000096:biosynthesis
chemical_list: D012310:Ristocetin; D016718:Arachidonic Acid; D013928:Thromboxane A2; D000244:Adenosine Diphosphate; D003094:Collagen; D011464:Epoprostenol