Pérez de la Mora M, Ferré S, Fuxe K
Departmento de Neurociencias, Universidad Nacional Autonoma de México, México, D.F., México.
Neurochem Res. 1997 Aug;22(8):1051-4. doi: 10.1023/a:1022439212836.
Recent evidence has shown in membrane preparations that the binding of one ligand to its receptor is able to modify the binding parameters of a second receptor (receptor-receptor interactions), allowing the modulation of incoming signals onto a neuron. To further understand the gamma-amino-butyric acid (GABA)-dopamine (DA) interactions in the neostriatum we have carried out experiments to explore whether an activation of the GABA(A) receptor could affect the binding characteristics of the D2 DA receptor in membrane preparations of the rat neostriatum. The results show the GABA (30-100 nM) significantly increases the dissociation constant of the high affinity (KH) D2 DA binding site (labelled with the selective D2 DA receptor antagonist [3H]raclopride and that such an effect is fully counteracted by the GABA(A) receptor antagonist bicuculline (1 microM). It is suggested that such putative GABA(A)/D2 receptor-receptor interactions may take place in the somato-dendritic membrane of the striato-pallidal GABA neurons and that it may modulate the inhibitory effects of DA on these neurons, mediated via D2 receptors.
最近有证据表明，在膜制剂中，一种配体与其受体的结合能够改变第二种受体的结合参数（受体 - 受体相互作用），从而调节传入神经元的信号。为了进一步了解新纹状体中γ-氨基丁酸（GABA） - 多巴胺（DA）的相互作用，我们进行了实验，以探究GABA(A)受体的激活是否会影响大鼠新纹状体膜制剂中D2 DA受体的结合特性。结果表明，GABA（30 - 100 nM）显著增加了高亲和力（KH）D2 DA结合位点的解离常数（用选择性D2 DA受体拮抗剂[3H]雷氯必利标记），并且GABA(A)受体拮抗剂荷包牡丹碱（1 microM）可完全抵消这种作用。有人提出，这种假定的GABA(A)/D2受体 - 受体相互作用可能发生在纹状体 - 苍白球GABA神经元的体树突膜中，并且它可能调节DA通过D2受体介导的对这些神经元的抑制作用。
