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咖啡因会改变A2A腺受体及其在人体血小板中的功能
K Varani1, F Portaluppi, S Merighi
1Department of Clinical and Experimental Medicine, University of Ferrara, San Raffaele Science Park, Milan, Italy.
Circulation
|May 20, 1999
概括
重复摄入咖啡因可以提高人体血小板A2A腺受体的调节. 这导致血小板反应的敏感性增加,例如cAMP积累和聚合减少,在A2A受体刺激后.
科学领域:
- 药理学 药理学是指药理学的学科.
- 分子生物学分子生物学
- 心血管研究研究心血管研究
背景情况:
- 咖啡因主要通过阻断腺受体而起作用,这些受体包括A1,A2A,A2B和A3亚型.
- 氨酸受体在各种生理过程中起着至关重要的作用,包括血小板功能.
研究的目的:
- 为了研究慢性咖啡因消费是否可调高人体血小板中的A2A腺受体.
- 为了确定这种上调是否与增加血小板对A2A受体刺激的敏感性有关.
主要方法:
- 人类志愿者每天服用750毫克咖啡因,持续一周.
- 血小板在基线 (禁食) 和咖啡因戒断后12小时和60小时收集.
- 使用放射性体结合 ([3H]SCH 58261) 测量了A2A受体密度.
- 在用A2A受体激动剂 (HE-NECA) 刺激后,评估了血小板反应,包括cAMP积累和聚合.
主要成果:
- 慢性咖啡因摄入显著增加了人体血小板中的A2A受体的密度 (Bmax).
- 从咖啡因禁用志愿者的血小板显示对A2A受体激动剂HE-NECA的敏感性增加.
- 这种敏感性是由HE-NECA增加cAMP积累 (降低EC50) 和抑制血小板聚合 (降低IC50) 所需的较低度证明的.
结论:
- 慢性咖啡因消费导致人类血小板上A2A腺受体的上调.
- 这种上调伴随着血小板对A2A受体激动剂刺激的反应能力提高,表明功能敏感化.
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