Wang J K
Program in Neurosciences, Tufts University School of Medicine, Boston, Massachusetts 02111.
J Neurochem. 1991 Sep;57(3):819-22. doi: 10.1111/j.1471-4159.1991.tb08224.x.
The wide-ranging neuronal actions of glutamate are thought to be mediated by postsynaptic N-methyl-D-aspartate (NMDA) and non-NMDA receptors. The present report demonstrates the existence of presynaptic glutamate receptors in isolated striatal dopaminergic nerve terminals (synaptosomes). Activation of these receptors, by NMDA in the absence of Mg2+ and presence of glycine and by non-NMDA agonists in the presence of Mg2+, results in Ca(2+)-dependent release of dopamine from striatal synaptosomes. The release stimulated by NMDA is blocked by Mg2+ and by selective NMDA antagonists, whereas the release stimulated by selective non-NMDA agonists is blocked by a non-NMDA antagonist but not by Mg2+ or NMDA antagonists. Thus, these presynaptic glutamate receptors, localized on dopaminergic terminals in the striatum, appear to be pharmacologically similar to both the NMDA and the non-NMDA postsynaptic receptors. By modulating the release of dopamine, these presynaptic receptors may play an important role in transmitter interactions in the striatum.
谷氨酸广泛的神经元作用被认为是由突触后 N-甲基-D-天冬氨酸（NMDA）和非 NMDA 受体介导的。本报告证明了在分离的纹状体多巴胺能神经末梢（突触体）中存在突触前谷氨酸受体。在不存在 Mg2+且存在甘氨酸的情况下，NMDA 以及在存在 Mg2+的情况下非 NMDA 激动剂激活这些受体，会导致纹状体突触体中多巴胺以 Ca(2+)依赖的方式释放。NMDA 刺激的释放被 Mg2+和选择性 NMDA 拮抗剂阻断，而选择性非 NMDA 激动剂刺激的释放被非 NMDA 拮抗剂阻断，但不被 Mg2+或 NMDA 拮抗剂阻断。因此，这些位于纹状体多巴胺能末梢的突触前谷氨酸受体，在药理学上似乎与 NMDA 和非 NMDA 突触后受体都相似。通过调节多巴胺的释放，这些突触前受体可能在纹状体中的递质相互作用中发挥重要作用。
