Summary
The pharmacological properties of YM-254890,a specific Gαq/11 inhibitor, on acute thrombosis and chronic neointima formation after vascular injury
have been investigated. FeCl3 was used to induce vascular injury in the carotid artery of mice. For the thrombosis
studies, the test drug was either intravenously or orally administered before vascular
injury. For the neointima studies, the test drug was orally administered 1 h before
and twice daily for 1 week after vascular injury. Histological analysis was then performed
3 weeks later. YM-254890 significantly inhibited ex vivo platelet aggregation 5 min after intravenous bolus injection at 0.03 mg/kg or more,
and 1 h after oral administration at 1 mg/kg. YM-254890 significantly inhibited thrombus
formation after intravenous bolus injection at 0.03 mg/kg as well as after oral administration
at 1 mg/kg, but tail transection bleeding time was significantly prolonged at 0.1
mg/kg for intravenous injection and 3 mg/kg for oral administration. Furthermore,
oral administration of YM-254890 dose-dependently inhibited neointima formation 3
weeks after vascular injury with significant effects at 1 mg/kg twice daily for 1
week. Clopidogrel also significantly inhibited neointima formation at its antithrombotic
dose, but its inhibitory potency was less than that of YM-254890. However, YM-254890
significantly reduced systemic blood pressure at doses 3 times higher than those that
produced significant inhibitory effects on thrombosis and neointima formation. Though
the systemic use of YM-254890 may be limited, owing to its narrow therapeutic window,
this unique compound is a useful research tool for investigating the physiological
roles of Gαq/11.
Keywords
Bleeding time - Gα
q/11 inhibitor - neointima formation - platelets - thrombosis