Jakubowski Z, Skowroński R, Matecki A, Mohuczy D, Pawełczyk T, Stepiński J, Angielski S
Department of Clinical Biochemistry, Medical Academy, Gdańsk, Poland.
Pol J Pharmacol Pharm. 1992 Jul-Aug;44(4):373-82.
High affinity binding sites for adenosine were identified in rat kidney cortex basolateral membranes. Kinetic analysis indicates two sets of [3H]adenosine, [3H]ADO, binding sites, one with high affinity and Kd = 0.84 +/- 0.25 microM, one with low affinity and Kd = 4.74 +/- 0.37 microM. The ADO receptors were further characterized using ADO analogs as binding inhibitors. The most potent inhibitor of [3H]ADO binding was N-methyl-adenosine with a Kd of 5 microM, whereas 2-deoxyadenosine was about 50 times less potent. The binding of [3H]phenylisopropyladenosine, [3H]PIA, and [3H]-N-ethylcarboxamidoadenosine, [3H]NECA, to basolateral membranes was rapid and reversible. The Scatchard plot of [3H]PIA binding showed monophasic curves for experiments performed at 0 degrees C and 37 degrees C. The apparent Kd of [3H]PIA binding at 0 degrees C was 0.19 +/- 0.05 nM and 0.34 +/- 0.07 nM at 37 degrees C. The binding of [3H]NECA to basolateral membranes was found with an apparent affinity Kd of 110 +/- 50 nM at 0 degrees C. Pretreatment of membranes with N-ethylmaleimide (NEM) inhibited the [3H]PIA binding and did not affect the [3H]NECA binding. These results demonstrate that both A1 and A2 adenosine receptors are present in basolatertal membranes of rat kidney.
在大鼠肾皮质基底外侧膜中鉴定出了腺苷的高亲和力结合位点。动力学分析表明存在两组[3H]腺苷（[3H]ADO）结合位点，一组具有高亲和力，解离常数（Kd）=0.84±0.25微摩尔，另一组具有低亲和力，Kd = 4.74±0.37微摩尔。使用腺苷类似物作为结合抑制剂对腺苷受体进行了进一步表征。[3H]ADO结合的最有效抑制剂是N-甲基腺苷，Kd为5微摩尔，而2-脱氧腺苷的效力约低50倍。[3H]苯基异丙基腺苷（[3H]PIA）和[3H]-N-乙基羧酰胺基腺苷（[3H]NECA）与基底外侧膜的结合迅速且可逆。[3H]PIA结合的Scatchard图在0℃和37℃进行的实验中显示为单相曲线。[3H]PIA在0℃结合的表观Kd为0.19±0.05纳摩尔，在37℃为0.34±0.07纳摩尔。发现[3H]NECA与基底外侧膜的结合在0℃时表观亲和力Kd为110±50纳摩尔。用N-乙基马来酰亚胺（NEM）预处理膜可抑制[3H]PIA结合，且不影响[3H]NECA结合。这些结果表明A1和A2腺苷受体均存在于大鼠肾的基底外侧膜中。
