Thromboxane A 2 Receptor Density Increases during Chronic Exposure to Thromboxane A 2 Receptor Antagonists after Porcine Carotid Bypass

Abstract

Domestic swine (n = 12 in each group) were randomized to daily treatment with the thromboxane A₂ (TXA₂) receptor antagonist BMS-180291 (group I), aspirin (group II), or no drug (group III) prior to prosthetic carotid graft implantation. Platelet and arterial wall receptor density were measured by equilibrium binding using ¹²⁵I-BOP. At 6 weeks, means (s.e.m.) platelet receptor density (pmol/mg) had increased in groups I (3.3(0.6) versus 1.8(0.3); P<0.05) and II (2.6(0.6) versus 1.7(0.2); P<0.05), but not in group III (1.3(0.3) versus 1.2(0.2)). Aortic membrane TXA₂ receptor density (fmol/mg) was significantly greater (P<0.05) in groups I (150(50)) and II (68(10)) compared with group III (39(6)). Chronic exposure to a TXA₂ receptor antagonist or aspirin is associated with increased platelet and aortic receptor density in pigs. Published by Elsevier Science Ltd.