Summary
N (7-carboxyheptyl) imidazole is an inhibitor of platelet thromboxane synthetase that
has no effect on the cyclooxygenase activity. An oral dose of the substance to rats
(10 mg/kg) prolonged tail bleeding time from 170 ± 13 sec to 284 ± 22 sec. This oral
dose also inhibited platelet thromboxane B2 production induced by collagen ex vivo but had little effect on the aggregation dose
response curve. There was no effect on thrombin-induced aggregation.
Neither the thrombocytopenia induced by the Arthus reaction nor thrombus formation
on an implanted cotton thread were inhibited by oral doses of carboxyheptylimidazole
up to 30 mg/kg. Similarly neither the prothrombin nor activated partial thromboplastin
time were affected.
It is postulated that this thromboxane synthetase inhibitor prolongs bleeding time
not by inhibiting platelet aggregation or blood coagulation but rather by preventing
the vasoconstriction which would normally be caused by thromboxane A2.
Key words
Keywords Bleeding time - Thromboxane synthetase inhibitor - Thromboxane B
2
- Platelet aggregation
