Comparison of the Inhibitory Effects of the TXA2 Receptor Antagonist, Vapiprost, and Other Antiplatelet Drugs on Arterial Thrombosis in Rats: Possible Role of TXA2

Yoshiharu Takiguchi; Kouichirou Wada; Mitsuyoshi Nakashima

doi:10.1055/s-0038-1646297

Thrombosis and Haemostasis, Table of Contents

Thromb Haemost 1992; 68(04): 460-463
DOI: 10.1055/s-0038-1646297

Original Article

Schattauer GmbH Stuttgart

Comparison of the Inhibitory Effects of the TXA₂ Receptor Antagonist, Vapiprost, and Other Antiplatelet Drugs on Arterial Thrombosis in Rats: Possible Role of TXA₂

Yoshiharu Takiguchi

The Department of Pharmacology, Hamamatsu University School of Medicine, Hamamatsu, Japan

,

Kouichirou Wada

The Department of Pharmacology, Hamamatsu University School of Medicine, Hamamatsu, Japan

,

Mitsuyoshi Nakashima

The Department of Pharmacology, Hamamatsu University School of Medicine, Hamamatsu, Japan

› Author Affiliations

Abstract

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Summary

The antithrombotic effect of the thromboxane A₂ receptor antagonist, vapiprost, was compared with those of other antiplatelet drugs using an arterial thrombosis model which utilized photochemical reaction in the rat femoral artery. Vapiprost prolonged the time required to occlude the artery with thrombus and inhibited collagen-induced rat platelet aggregation in whole blood ex vivo, in a dose-dependent manner. The potency ranking of antithrombotic effect was vapiprost > ketanserin (serotonin 5-HT₂ receptor antagonist) >> ticlopidine (inhibitor of ADP-induced platelet aggregation) = dipyridamole (adenosine uptake inhibitor) >aspirin (cyclooxygenase inhibitor). On the other hand, the ranking of antiplatelet effect was ticlopidine ≥vapiprost ≥aspirin. Ketanserin and dipyridamole were ineffective. Relative to their antiplatelet effect, vapiprost and ketanserin had powerful antithrombotic effects. It is possible that the potent antithrombotic effects of vapiprost and ketanserin in vivo reflect the ability of these drugs to inhibit mediator-induced vascular contractions in addition to platelet aggregation. The results of the present study also suggest that TXA₂ may play an important role in thrombogenesis in rats.

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References

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