Effects of urapidil on 5-hydroxytryptamine induced platelet aggregation and on 14C-5-hydroxytryptamine uptake in platelets.
Urapidil inhibits the 5HT induced human platelet aggregation and the 5HT uptake by platelets in vitro and ex vivo. The aggregation was inhibited with a KI-value of 8.8 microM and the 5HT uptake in a noncompetitive way with KI1 = 15.3 microM and K12 = 10.6 microM. In vivo, the 5HT induced platelet aggregation was increased 4 h after oral administration of 60 mg urapidil. Subsequently, the aggregation decreased and reached a minimum at various times in the different volunteers. Eight h after oral administration of 60 mg urapidil, the 5HT uptake velocity was reduced approximately 40%.
Storck
J
J
Institut für klinische Pharmakologie, J.W-Goethe-Universität Frankfurt, FRG.
Ochs
J G
JG
Kirsten
R
R
D000284:Administration, Oral; D000328:Adult; D001792:Blood Platelets / Q000378:metabolism; D002250:Carbon Radioisotopes; D004837:Epinephrine / Q000037:antagonists & inhibitors; D006801:Humans; D007650:Ketanserin / Q000494:pharmacology; D009257:Nafronyl / Q000494:pharmacology; D010879:Piperazines / Q000008:administration & dosage / Q000494:pharmacology*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D011224:Prazosin / Q000494:pharmacology; D012701:Serotonin / Q000378:metabolism / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology*
D002250:Carbon Radioisotopes; D010879:Piperazines; D010975:Platelet Aggregation Inhibitors; D012702:Serotonin Antagonists; D012701:Serotonin; D009257:Nafronyl; D007650:Ketanserin; C015568:urapidil; D011224:Prazosin; D004837:Epinephrine