Serotonin-sensitive adenylate cyclase and [3]serotonin binding sites in the CNS of the rat—I: Kinetic parameters and pharmacological properties
Serotonin-sensitive adenylate cyclase and [3]serotonin binding sites in the CNS of the rat—I: Kinetic parameters and pharmacological properties
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大鼠中枢神经系统中血清素敏感的腺苷酸环化酶和[3]血清素结合位点—I：动力学参数和药理学特性
DOI：
10.1016/0006-2952(80)90348-2
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发表时间：
1980
影响因子：
5.8
通讯作者：
M. Hamon
中科院分区：
文献类型：
--
作者：
D. Nelson;A. Herbet;A. Enjalbert;J. Bockaert;M. Hamon
比较了腺苷酸环化酶连接的5-HT受体和[3H]-5-HT高亲和力结合位点在新生大鼠中枢神经系统中的动力学和药理学性质。在正常实验条件下，5-HT对其特异性结合位点（Kd= 1 ~ 2 nM）的表观亲和力远高于与腺苷酸环化酶偶联受体（KAapp = 0.5 ~ 1.0 μM）的表观亲和力。当在环化酶实验条件下测量时，结合的表观kd增加到11.9 nM，这一值仍然比表征5-HT活化腺苷酸环化酶的kaapp低40多倍。GTP影响[3H]-5-HT和5- ht敏感腺苷酸环化酶的结合。鸟苷核苷酸似乎对5-羟色胺激活腺苷酸环化酶至关重要，因为5-羟色胺在洗膜制备中是无活性的，除非加入GTP或GppNHp。在整个匀浆中，GTP增加了5-HT对受体-腺苷酸环化酶复合物的亲和力（在10μM GTP存在时KAapp = 0.33μM）。GTP和GppNHp降低了[3H]-5-HT的特异性结合，而GMP和ATP不降低。然而，诱导显著效果（小于0.10mM GTP）的浓度范围远远高于那些增加5- ht诱导的腺苷酸环化酶激活的浓度范围。这两种系统的药理学特征之间几乎没有共同之处。一组含有哌嗪杂环的5-HT激动剂[1- （m-三氟甲基苯基）哌嗪，喹嗪和MK-212]有效地将[3H]-5-HT从其结合位点移位，但对5-HT敏感的环化酶不起作用，既不影响基础也不影响5-HT刺激的cAMP产生。同样，一系列抑制[3H]-5-HT结合的5-HT拮抗剂的各自效力与5-HT诱导的cAMP产生之间没有相关性。这些数据表明，与腺苷酸环化酶相关的5-HT受体与[3H]-5-HT结合测量的5-HT受体并不相同，从而为大鼠脑中可能存在多种5-HT受体提供了证据。
The 5-HT receptor linked to adenylate cyclase and the high affinity binding site for [3H]-5-HT were compared on the basis of their kinetic and pharmacological properties in the CNS of new born rats. Under normal assay conditions, the apparent affinity of 5-HT for its specific binding sites (Kd= 1−2 nM) was much higher than that for the receptor coupled to adenylate cyclase (KAapp = 0.5−1.0 μM). When measured under the conditions of the cyclase assay, the apparentKdfor the binding was increased to 11.9 nM, a value which is still more than 40 times lower than theKAapp characterizing the activation of adenylate cyclase by 5-HT. GTP affected both the binding of [3H]-5-HT and the 5-HT-sensitive adenylate cyclase. Guanyl nucleotides appeared to be essential for the activation of adenylate cyclase by 5-HT as 5-HT was inactive in a preparation of washed membranes unless added in the presence of GTP or GppNHp. In whole homogenates, GTP increased the affinity of 5-HT for the receptor-adenylate cyclase complex (KAapp = 0.33μM in the presence of 10μM GTP). The specific binding of [3H]-5-HT was reduced by GTP and GppNHp but not GMP or ATP. However, the range of concentrations inducing a significant effect (⩾0.10mM GTP) was far higher than those which increased the 5-HT-induced activation of adenylate cyclase.There was little in common between the pharmacological profiles of the two systems. A group of 5-HT agonists containing a piperazine heterocycle [1- (m-trifluoromethylphenyl) piperazine, quipazine and MK-212] effectively displaced [3H]-5-HT from its binding sites but exerted no action on the 5-HT-sensitive cyclase, affecting neither the basal nor the 5-HT-stimulated cAMP production. Likewise, there was no correlation between the respective potencies of a series of 5-HT antagonists for inhibiting the binding of [3H]-5-HT and the 5-HT-induced cAMP production. These data suggest that the 5-HT receptor linked to adenylate cyclase is not identical with that which is measured by the binding of [3H]-5-HT and, thus, provide evidence for the possible existence of multiple receptors for 5-HT in the rat brain.