title: Influence of phentolamine on platelet aggregation, thromboxane B2 production and release reaction.
abstract: In this study the in vitro influence of phentolamine on platelet aggregating responses, thromboxane B2 (TxB2) production and intraplatelet cyclic AMP (cAMP) content has been investigated. The drug exerts a dose-dependent inhibitory effect on aggregating response to ADP, PAF, collagen, thrombin, sodium arachidonate and ionophore A 23187. Inhibiting phentolamine concentrations prevent also platelet release reaction and TxB2 synthesis. No significant influence on intraplatelet cAMP levels has been observed. The pre-incubation with low concentrations of ionophore A 23187 overcomes phentolamine inhibition of collagen-induced platelet aggregation. Our results provide evidence that phentolamine modulates the human platelet function and that its effects could also be related to a decrease of Ca++ availability.
authors.affiliation: Institute of Internal Medicine, University of Turin, Ospedale S. Luigi Gonzaga-Orbassano, Torino, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Anfossi
authors.forename: M
authors.initials: M
authors.lastname: Trovati
authors.forename: E
authors.initials: E
authors.lastname: Mularoni
authors.forename: M
authors.initials: M
authors.lastname: Lanzio
authors.forename: P
authors.initials: P
authors.lastname: Massucco
authors.forename: G
authors.initials: G
authors.lastname: Emanuelli
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D003094:Collagen / Q000494:pharmacology; D000242:Cyclic AMP / Q000097:blood; D006801:Humans; D066298:In Vitro Techniques; D010646:Phentolamine / Q000494:pharmacology*; D010972:Platelet Activating Factor / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects*; D013917:Thrombin / Q000494:pharmacology; D013929:Thromboxane B2 / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D001095:Arachidonic Acids; D010972:Platelet Activating Factor; D016718:Arachidonic Acid; D000001:Calcimycin; D013929:Thromboxane B2; D000244:Adenosine Diphosphate; D003094:Collagen; D000242:Cyclic AMP; D013917:Thrombin; D010646:Phentolamine