Department of Physiology and Pharmacology, Karolinska Institutet, S-171 77 Stockholm, Sweden.
Exp Cell Res. 2010 May 1;316(8):1284-8. doi: 10.1016/j.yexcr.2010.02.004. Epub 2010 Feb 11.
There are four adenosine receptors, A(1), A(2A), A(2B) and A(3), together forming a defined subgroup of G protein coupled receptors. They are well conserved and widely expressed. The endogenous agonist, adenosine, has a minimal concentration in body fluids (20-200 nM) that is sufficient to slightly activate the receptors where they are very highly expressed-as in the basal ganglia, on fat cells and in the kidney. Here adenosine can play a physiological role and here antagonists such as caffeine can have effects in healthy individuals. Adenosine levels rise in stress and distress (up to 30 microM in ischemia) and tend to minimize the risk for adverse outcomes by increasing energy supply and decreasing cellular work, by stimulating angiogenesis, mediating preconditioning and having multiple effects on immune competent cells. These pathophysiological roles of adenosine also offer some potential drug targets, but the fact that adenosine receptors are involved in so many processes does not simplify drug development.
有四种腺苷受体，A(1)、A(2A)、A(2B)和 A(3)，它们共同构成了 G 蛋白偶联受体的一个明确亚群。它们高度保守且广泛表达。内源性激动剂腺苷在体液中的浓度很低（20-200nM），足以轻微激活在高表达部位的受体，如基底神经节、脂肪细胞和肾脏。在这里，腺苷可以发挥生理作用，而咖啡因等拮抗剂在健康个体中也可以产生作用。在应激和痛苦时腺苷水平升高（在缺血时可达 30μM），通过增加能量供应和减少细胞工作、刺激血管生成、介导预处理以及对免疫活性细胞产生多种作用，降低发生不良后果的风险。腺苷的这些病理生理作用也提供了一些潜在的药物靶点，但事实上，腺苷受体参与了如此多的过程，这并没有简化药物开发。
