2-CHLORO-N-6-[H-3]CYCLOPENTYLADENOSINE ([H-3]CCPA) - A HIGH-AFFINITY AGONIST RADIOLIGAND FOR A1 ADENOSINE RECEPTORS
2-CHLORO-N-6-[H-3]CYCLOPENTYLADENOSINE ([H-3]CCPA) - A HIGH-AFFINITY AGONIST RADIOLIGAND FOR A1 ADENOSINE RECEPTORS
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DOI：
10.1007/bf00717744
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发表时间：
1989-12-01
影响因子：
3.6
通讯作者：
GRIFANTINI, M
中科院分区：
文献类型：
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作者：
KLOTZ, KN;LOHSE, MJ;GRIFANTINI, M
2-氯-N6-环戊基腺苷（CCPA）的氚化类似物，具有亚纳摩尔亲和力和10000倍的选择性A1腺苷受体的腺苷衍生物，已被检查作为一个新的激动剂放射性配体。制备比放射性为1.58 TBq/mmol（43 Ci/mmol）的[3 H]CCPA，并以可逆方式与大鼠脑细胞膜的A1受体结合，高亲和力KD值为0.2 nmol/l。在GTP存在下，确定激动剂结合的低亲和力状态的KD值为13 nmol/l。几种腺苷受体激动剂和拮抗剂的竞争[3 H]CCPA结合到大鼠脑细胞膜证实结合到A1受体。溶解的A1受体结合[3 H]CCPA与高亲和力状态具有相似的亲和力。在MgCl 2存在下，在溶解的受体处观察到降低的缔合速率，如激动剂[3 H]N6-苯基异丙基腺苷（[3 H]PIA）所示。[3 H]CCPA还用于检测大鼠心肌细胞膜（一种受体密度非常低的组织）中的A1受体。在这些膜中测定的KD值为0.4nmol/l，β max值为16 fmol/mg蛋白质。在人血小板膜中，在浓度高达400 nmol/l时未测得[3 H]CCPA的特异性结合，表明A2受体不结合[3 H]CCPA。基于对A1受体[3 h]的亚纳摩尔亲和力和高选择性，CCPA被证明是一种有用的激动剂放射性配体，用于表征受体密度非常低的组织中的A1腺苷受体。
The tritiated analogue of 2-chloro-N6-cyclopentyladenosine (CCPA), an adenosine derivative with subnanomolar affinity and a 10000-fold selectivity for A1 adenosine receptors, has been examined as a new agonist radioligand. [3H]CCPA was prepared with a specific radioactivity of 1.58 TBq/mmol (43 Ci/mmol) and bound in a reversible manner to A1 receptors from rat brain membranes with a high affinity KD-value of 0.2 nmol/l. In the presence of GTP a KD-value of 13 nmol/l was determined for the low affinity state for agonist binding. Competition of several adenosine receptor agonists and antagonists for [3H]CCPA binding to rat brain membranes confirmed binding to an A1 receptor. Solubilized A1 receptors bound [3H]CCPA with similar affinity for the high affinity state. At solubilized receptors a reduced association rate was observed in the presence of MgCl2, as has been shown for the agonist [3H]N6-phenylisopropyladenosine ([3H]PIA). [3H]CCPA was also used for detection of A1 receptors in rat cardio myocyte membranes, a tissue with a very low receptor density. A KD-value of 0.4 nmol/l and a .BETA.max-value of 16 fmol/mg protein was determined in these membranes. In human platelet membranes no specific binding of [3H]CCPA was measured at concentrations up to 400 nmol/l, indicating that A2 receptors did not bind [3H]CCPA. Based on the subnanomolar affinity and the high selectivity for A1 receptors [3h]CCPA proved to be a useful agonist radioligand for characterization of A1 adenosine receptors also in tissues with very low receptor density.