Sulotroban selectively inhibits thromboxane-receptor-mediated responses in the peripheral vascular bed of the cat.

Abstract

The effects of Sulotroban (BM 13.177, SK&F 95587) were investigated under conditions of controlled blood flow in the hindquarters and mesenteric vascular beds of the cat. Injections of the thromboxane (TX) A2 mimics, U46619 and U44069, caused dose-related increases in perfusion pressure. After administration of SK&F 95587, vasoconstrictor responses to the TXA2 mimics were reduced significantly, and the dose-response curves were shifted to the right in a parallel fashion. Responses to norepinephrine, phenylephrine, tyramine, endothelin-1, angiotensin II, BAY K8644, acetylcholine, sodium nitroprusside, isoproterenol, lemakalim, prostaglandin (PG) E1, and PGF2 alpha, agents which alter vascular resistance by a variety of mechanisms, were not changed by the TXA2 receptor antagonist. However, SK&F 95587 reduced mesenteric vasoconstrictor responses to PGD2. Results of the present study indicate that SK&F 95587 blocks TX-receptor-mediated responses in the hindquarters circulation of the cat in a competitive and selective manner and reduces mesenteric vascular responses to the TXA2 mimics, as well as PGD2. These data suggest that this antagonist would be useful in studies on the role of TXA2 in physiologic and pathophysiologic processes in the systemic vascular bed of the cat.