Wang J K, Andrews H, Thukral V
Program in Neurosciences, Tufts University School of Medicine, Boston, Massachusetts 02111.
J Neurochem. 1992 Jan;58(1):204-11. doi: 10.1111/j.1471-4159.1992.tb09297.x.
The wide-ranging neuronal actions of excitatory amino acids, such as glutamate, are thought to be mediated mainly by postsynaptic N-methyl-D-aspartate (NMDA) and non-NMDA receptors. We now report the existence of presynaptic glutamate receptors in isolated nerve terminals (synaptosomes) prepared from hippocampus, olfactory bulb, and cerebral cortex. Activation of these receptors by NMDA or non-NMDA agonists, in a concentration-dependent manner, resulted in Ca(2+)-dependent release of noradrenaline from vesicular transmitter stores. The NMDA-stimulated release was potentiated by glycine and was blocked by Mg2+ and selective NMDA antagonists. In contrast, release stimulated by selective non-NMDA agonists was blocked by 6-cyano-7-nitroquinoxaline-2,3- dione, but not by Mg2+ or NMDA antagonists. Our data suggest that the presynaptic glutamate receptors can be classified pharmacologically as both the NMDA and non-NMDA types. These receptors, localized on nerve terminals of the locus ceruleus noradrenergic neurons, may play an important role in interactions between noradrenaline and glutamate.
兴奋性氨基酸（如谷氨酸）具有广泛的神经元作用，一般认为其主要通过突触后N-甲基-D-天冬氨酸（NMDA）受体和非NMDA受体介导。我们现在报告，在从海马体、嗅球和大脑皮层制备的分离神经末梢（突触体）中存在突触前谷氨酸受体。NMDA或非NMDA激动剂以浓度依赖的方式激活这些受体，导致去甲肾上腺素从囊泡递质储存中以钙依赖的方式释放。NMDA刺激的释放被甘氨酸增强，并被Mg2+和选择性NMDA拮抗剂阻断。相比之下，选择性非NMDA激动剂刺激的释放被6-氰基-7-硝基喹喔啉-2,3-二酮阻断，但不被Mg2+或NMDA拮抗剂阻断。我们的数据表明，突触前谷氨酸受体在药理学上可分为NMDA型和非NMDA型。这些受体位于蓝斑去甲肾上腺素能神经元的神经末梢上，可能在去甲肾上腺素和谷氨酸之间的相互作用中起重要作用。
