Multiple α2‐Noradrenergic Receptor Sites in Rat Brain: Selective Regulation of High‐Affinity [3H] Clonidine Binding by Guanine Nucleotides and Divalent Cations
Multiple α2‐Noradrenergic Receptor Sites in Rat Brain: Selective Regulation of High‐Affinity [3H] Clonidine Binding by Guanine Nucleotides and Divalent Cations
复制标题
大鼠脑中多个 α2-去甲肾上腺素能受体位点：鸟嘌呤核苷酸和二价阳离子对高亲和力 [3H] 可乐定结合的选择性调节
DOI：
10.1111/j.1471-4159.1980.tb06607.x
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发表时间：
1980
影响因子：
4.7
通讯作者：
S. Snyder
中科院分区：
文献类型：
--
作者：
B. Rouot;D. U'prichard;S. Snyder
动力学和平衡实验均表明，大鼠大脑皮层膜中存在与 α2- 去甲肾上腺素能受体相关的不同高亲和力和低亲和力 [3H] 可乐定结合。鸟嘌呤核苷酸选择性地减少高亲和力[3H]可乐定结合位点的数量，而不影响低亲和力位点。核苷酸的影响是由 GTP、其非代谢类似物、鸟苷基-5′-亚胺二磷酸和 GDP 产生的，但不受 GMP、ADP、ATP 和 AMP 的影响。相反，二价阳离子增加高亲和力[3H]可乐定结合，这种作用在低亲和力位点并不明显。锰是最有效的二价阳离子，而镁和钙的活性较低。二价阳离子和鸟嘌呤核苷酸似乎对 α2 受体产生相互作用，而不是简单的相加影响。钠对 [3H] 可乐定的 α2 受体结合的抑制作用对高亲和力和低亲和力 [3H] 可乐定结合产生相同程度的影响。
Both kinetic and equilibrium experiments indicate the presence of distinct high‐ and low‐affinity [3H]clonidine binding associated with α2‐ noradrenergic receptors in rat cerebral cortex membranes. Guanine nucleotides selectively decrease the numbers of high‐affinity [3H]clonidine binding sites, with no influence on the low‐affinity sites. The influence of nucleotides is exerted by GTP, its nonmetabolized analogue, guanyl‐5′‐yl imidodiphosphate, and GDP–but not by GMP, ADP, ATP, and AMP. In contrast, divalent cations increase high‐affinity [3H]clonidine binding‐an effect not evident at low‐affinity sites. Manganese is the most potent of the divalent cations, while magnesium and calcium are less active. Divalent cations and guanine nucleotides appear to elicit interactive rather than simply additive influences upon α2‐receptors. The inhibitory influence of sodium upon α2‐receptor binding of [3H]clonidine is exerted to the same extent upon both high‐ and low‐affinity [3H]clonidine binding.