体内给予血栓素A2（TxA2）受体抑制剂后，TxA2血小板结合位点的急性减少。

Acute reduction of TxA2 platelet binding sites after in vivo administration of a TxA2 receptor inhibitor.

Modesti P A, Colella A, Cecioni I, Gensini G F, Abbate R, Neri Serneri G G

Clinica Medica I, University of Florence, Italy.

Br J Clin Pharmacol. 1991 Apr;31(4):439-43. doi: 10.1111/j.1365-2125.1991.tb05560.x.

Abstract

Picotamide has been shown to interfere competitively with the thromboxane A2 (TxA2) platelet receptor. In the present study the effect of in vivo administration of picotamide on TxA2 human platelet receptors was investigated in 10 healthy subjects. 2. Picotamide (300 mg x 3 daily) or placebo were administered in a double-blind, cross-over, placebo controlled study, each treatment lasting 1 week with a 2 week interval period. TxA2 receptors were investigated by a direct radioligand binding assay method employing [125I]-PTA-OH as labelled ligand. Platelet studies were performed on the first day of treatment immediately before and 2, 4 and 8 h after the ingestion of the drug. The effects of chronic administration were assessed on the seventh day. 3. Two and 4 h after the administration of picotamide 300 mg orally platelet TxA2 receptors were significantly reduced from 1366 +/- 237 to 957 +/- 221 (P less than 0.05) and 753 +/- 119 receptors/platelet (mean +/- s.d.) (P less than 0.03). After 8 h platelet receptor population was restored (1362 +/- 324, NS). The same pattern was observed after 7 days of treatment. Thus picotamide seems to induce a short lasting down regulation of platelet TxA2 receptors.

摘要

已证明吡考他胺可竞争性地干扰血栓素A2（TxA2）血小板受体。在本研究中，对10名健康受试者研究了体内给予吡考他胺对TxA2人血小板受体的影响。2. 在一项双盲、交叉、安慰剂对照研究中给予吡考他胺（每日3次，每次300mg）或安慰剂，每种治疗持续1周，间隔2周。采用[125I]-PTA-OH作为标记配体的直接放射性配体结合测定法研究TxA2受体。在治疗的第一天，即在服药前以及服药后2、4和8小时进行血小板研究。在第七天评估长期给药的效果。3. 口服300mg吡考他胺后2小时和4小时，血小板TxA2受体从1366±237显著减少至957±221（P<0.05）和753±119个受体/血小板（平均值±标准差）（P<0.03）。8小时后血小板受体数量恢复（1362±324，无显著性差异）。治疗7天后观察到相同的模式。因此，吡考他胺似乎可诱导血小板TxA2受体的短期下调。