Fino Elodie, Glowinski Jacques, Venance Laurent
Dynamique et Physio-pathologie des Réseaux Neuronaux, INSERM U667, Collège de France, 75231 Paris Cedex 05, France.
Neurosci Res. 2007 Jul;58(3):305-16. doi: 10.1016/j.neures.2007.04.002. Epub 2007 Apr 7.
The striatum, the main input nucleus of basal ganglia, receives a massive innervation from the entire cerebral cortex and is in charge of the detection of behaviorally relevant signals. In turn, via its projections to the output nuclei of basal ganglia, the striatum contributes to the organization of appropriate compartmental responses. Substantia nigra pars compacta dopaminergic neurons project predominantly to the striatum and regulate striatal functions. Implications of dopaminergic receptors on the physiology of striatal neurons are now well documented. By contrast, the effects of acute dopamine depletion on striatal neurons remain poorly explored. Here, the alpha-methyl-para-tyrosine was used to deplete dopamine from rat brain slices. We analyzed the consequences of a alpha-methyl-para-tyrosine treatment on membrane properties of striatal neurons: the medium-sized spiny neurons and the interneurons (GABAergic, cholinergic and NO-synthase). After acute dopamine depletion, medium-sized spiny neurons became more excitable. GABAergic interneurons became less excitable whereas cholinergic cells displayed an increased excitability. NO-synthase-containing interneurons did not show noticeable changes in their excitability. Such membrane properties changes indicate that striatal circuits should undergo major alteration in cortico-basal ganglia information processing.
纹状体是基底神经节的主要输入核，接受来自整个大脑皮层的大量神经支配，并负责检测与行为相关的信号。反过来，纹状体通过其向基底神经节输出核的投射，有助于组织适当的分区反应。黑质致密部多巴胺能神经元主要投射到纹状体并调节纹状体功能。多巴胺能受体对纹状体神经元生理学的影响现在已有充分记录。相比之下，急性多巴胺耗竭对纹状体神经元的影响仍未得到充分研究。在这里，使用α-甲基-对-酪氨酸来耗尽大鼠脑片中的多巴胺。我们分析了α-甲基-对-酪氨酸处理对纹状体神经元膜特性的影响：中型棘状神经元和中间神经元（γ-氨基丁酸能、胆碱能和一氧化氮合酶阳性）。急性多巴胺耗竭后，中型棘状神经元变得更易兴奋。γ-氨基丁酸能中间神经元变得不易兴奋，而胆碱能细胞的兴奋性增加。含一氧化氮合酶的中间神经元的兴奋性没有明显变化。这种膜特性的变化表明，在皮质-基底神经节信息处理中，纹状体回路应该会发生重大改变。
