PARADOXICAL GABA EXCITATION OF NIGRAL DOPAMINERGIC CELLS - INDIRECT MEDIATION THROUGH RETICULATA INHIBITORY NEURONS
PARADOXICAL GABA EXCITATION OF NIGRAL DOPAMINERGIC CELLS - INDIRECT MEDIATION THROUGH RETICULATA INHIBITORY NEURONS
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DOI：
10.1016/0014-2999(79)90283-8
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发表时间：
1979-01-01
影响因子：
5
通讯作者：
BUNNEY, BS
中科院分区：
文献类型：
--
作者：
GRACE, AA;BUNNEY, BS
大鼠的生化和电生理研究表明，GABA激动剂增加了黑质致密带（ZC）中多巴胺能神经元的活性，尽管已知GABA能输入到ZC细胞。利用单单元记录技术对这种矛盾效应进行了研究。位于SN网状带（ZR）的神经元群对GABA的敏感程度是ZC神经元的20倍。通过微离子导入的GABA使ZC细胞活性增加，而以同样方式导入的谷氨酸对ZC细胞产生抑制作用。后一种效应被低剂量的微毒素阻断。Muscimol （i.v）在相同剂量下引起ZR细胞活性的降低，引起ZC细胞放电率的平行增加。ZC细胞显然接受来自ZR细胞的抑制性GABA能输入，而ZR细胞又被低剂量的GABA激动剂抑制。这种解剖结构可以解释GABA激动剂对ZC神经元活动的矛盾兴奋作用。
Biochemical and electrophysiological studies in rats suggest that GABA agonists increase the activity of dopaminergic neurons in the zona compacta (ZC) of the substantia nigra (SN) despite a known GABAergic input to ZC cells. Using single-unit recording techniques this paradoxical effect was studied. A population of neurons located in the zona reticulata (ZR) of the SN was 20 times more sensitive to iontophoretically applied GABA than ZC neurons. GABA introduced by microiontophoresis into the ZR caused an increase in ZC cells activity while glutamic acid introduced in the same manner produced an inhibition of ZC cells. The latter effect was blocked by low doses of picrotoxin. Muscimol (i.v.) caused a decrease in ZR cell activity at the same dose that caused a parallel increase in ZC cell firing rate. ZC cells apparently receive an inhibitory GABAergic input from ZR cells that are in turn inhibited by low doses of GABA agonists. Such an anatomical arrangement would account for the paradoxical excitatory effect of GABA agonists on ZC neuron activity.