Nitric oxide and prostacyclin inhibit fetal platelet aggregation: a response similar to that observed in adults.
OBJECTIVE
We evaluated the relative importance of two endothelium-derived substances, prostacyclin and nitric oxide, in their ability to inhibit aggregation of fetal and maternal platelets.


METHODS
The effects of various concentrations of prostacyclin and S-nitroso-N-acetylpenicillamine (which releases nitric oxide) on platelet aggregation were studied by means of platelet-rich plasma from at least five to six subjects per group. Fetal blood was collected from umbilical vein at delivery. Maternal venous blood was collected within 4 hours of delivery. Platelet aggregation was monitored with a platelet aggregation profiler. Adenosine diphosphate was used as the aggregating agent. Statistical differences between means were evaluated with two-way analysis of variance or Student t test.


RESULTS
Prostacyclin and S-nitroso-N-acetylpenicillamine inhibited aggregation of fetal and maternal platelets, but prostacyclin was more potent. Fetal platelets were more sensitive than maternal platelets to prostacyclin and S-nitroso-N-acetylpenicillamine.


CONCLUSIONS
Prostacyclin appears to be more important in preventing aggregation of platelets in the feto placental circulation.
Varela
A F
AF
Departments of Obstetrics and Gynecology, University of California, Los Angeles School of Medicine 90024-1740.
Runge
A
A
Ignarro
L J
LJ
Chaudhuri
G
G
D000244:Adenosine Diphosphate / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects; D004837:Epinephrine / Q000494:pharmacology; D011464:Epoprostenol / Q000494:pharmacology*; D005260:Female; D005312:Fetal Blood / Q000187:drug effects*; D006801:Humans; D009569:Nitric Oxide / Q000494:pharmacology*; D009994:Osmolar Concentration; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects*; D011247:Pregnancy / Q000097:blood; D026423:S-Nitroso-N-Acetylpenicillamine
D009569:Nitric Oxide; D000244:Adenosine Diphosphate; D026423:S-Nitroso-N-Acetylpenicillamine; D011464:Epoprostenol; D010396:Penicillamine; D004837:Epinephrine