Zhang Hui, Sulzer David
Department of Neurology, Columbia University, New York, New York 10032, USA.
J Neurosci. 2003 Nov 19;23(33):10585-92. doi: 10.1523/JNEUROSCI.23-33-10585.2003.
Cortical glutamate and substantia nigra dopamine (DA) afferents converge onto the dendritic spines of medium spiny neurons (MSNs) in the striatum where they act to modulate motor and cognitive functions. The released DA spills over from its synapse and is thought to regulate glutamatergic input by acting on distal DA receptors located on corticostriatal axon terminals. By monitoring evoked DA release directly using fast-scan cyclic voltammetry, we report a reciprocal modulation by glutamate spillover on evoked striatal DA release, induced by either glutamate uptake blockade or high-frequency stimulation of corticostriatal tracts. We demonstrate that this modulation is attributable to the activation of group I metabotropic glutamate receptors. Thus, under conditions in which glutamate escapes the confines of its synapse, it can elicit the presynaptic suppression of dopaminergic neurotransmission.
皮质谷氨酸能和黑质多巴胺（DA）传入纤维汇聚到纹状体中等棘状神经元（MSN）的树突棘上，在那里它们调节运动和认知功能。释放的多巴胺从其突触溢出，被认为通过作用于位于皮质纹状体轴突终末的远端多巴胺受体来调节谷氨酸能输入。通过使用快速扫描循环伏安法直接监测诱发的多巴胺释放，我们报告了谷氨酸溢出对诱发的纹状体多巴胺释放的相互调节作用，这是由谷氨酸摄取阻断或皮质纹状体束的高频刺激所诱导的。我们证明这种调节作用归因于I组代谢型谷氨酸受体的激活。因此，在谷氨酸逸出其突触范围的情况下，它可以引发多巴胺能神经传递的突触前抑制。
