Effect of thromboxane and serotonin receptor antagonists on intracoronary platelet deposition in dogs with experimentally stenosed coronary arteries.

摘要: We have reported previously that thromboxane A2 (TXA2) and serotonin (5-HT, 5-hydroxytryptamine) are important mediators of cyclic flow variations (CFVs) in a canine model coronary artery stenosis endothelial injury. The present study tested the hypothesis TXA2 receptor antagonist is more effective reducing intracoronary platelet deposition at sites injury severe than 5-HT2 antagonist. CFVs developed after placing plastic constrictor around left anterior descending (LAD) 51 56 dogs. Autologous platelets labeled with 111In were injected 48 animals. Ten control dogs (group 1A) killed observed for 1 hour nadir blood flow. Five 1B) did not develop placement constrictor. abolished SQ 28668 (2.75 +/- 0.36 mg/kg, group 2) 29548 (0.45 0.1 3), two different PGH2 antagonists, eight 10 six seven dogs, respectively. In 4), ketanserin (0.66 0.12 mg/kg), 2, 3, 4 respective drugs given so minimal dose required to was administered. 5), higher (i.e., 1.5 mg/kg) used abolish CFVs. At death, evaluated by calculating LAD accumulation ratio (111In activity LAD/111In circumflex artery) 43 and, 22 microscopic examination LAD. A marked found 1A stenotic site segments immediately distal it. significantly reduced both low high doses compared (p less 0.001). However, antagonists further ketanserin-treated animals 0.01). Microscopic confirmed these findings. conclude 29548, reduce residual associated this effectively ketanserin,