Glycine Binding Sites of Presynaptic Nmda Receptors May Tonically Regulate Glutamate Release in the Rat Visual Cortex.
From: Dept. of Physiology, School of Medicine, Xi’an Jiaotong University, Zhuque Dajie 205, Xi’an, Shaanxi 710061, PR China.
Journal of neurophysiology
- Publish Date: Jan 2007
- ISSN: 0022-3077
- Volume: 97
- Issue: 1
- Pages: 817-23
- Medium: Print
- Language: English
- Citation (JAMA): Li Yan-Hai, Han Tai-Zhen, et al. Glycine Binding Sites of Presynaptic Nmda Receptors May Tonically Regulate Glutamate Release in the Rat Visual Cortex.. J. Neurophysiol. Jan 2007;97:817-23
Abstract
In the CNS, activation of N-methyl-D-aspartate receptor (NMDA-R) glycine binding sites is a prerequisite for activation of postsynaptic NMDA-Rs by the excitatory neurotransmitter glutamate. Here we provide electrophysiological evidence that the glycine binding sites of presynaptic NMDA-Rs regulate glutamate release in layer II/III pyramidal neurons of the rat visual cortex. Specifically, our results reveal that the frequency of miniature excitatory postsynaptic currents is significantly reduced by 7-chloro-kynurenic acid (7-Cl KYNA), a NMDA-R glycine binding site antagonist, and glycine or D-serine reverses this effect. Similar results are obtained when the open-channel NMDA receptor blocker, MK-801, is included in the recording pipette. Our data indicate that the glycine binding site of postsynaptic NMDA-Rs is not saturated. Moreover, they suggest that presynaptic NMDA-Rs are located in layer II/III pyramidal neurons of the rat visual cortex and that the glycine binding site of presynaptic NMDA-Rs tonically regulates glutamate release.
Mesh Headings (Keywords): Animals, Binding Sites, Binding, Competitive, Dizocilpine Maleate, Excitatory Amino Acid Antagonists, Excitatory Postsynaptic Potentials, Glutamic Acid, Glycine, Kynurenic Acid, Organ Culture Techniques, Presynaptic Terminals, Pyramidal Cells, Rats, Rats, Sprague-Dawley, Receptors, N-Methyl-D-Aspartate, Synaptic Transmission, Visual Cortex
Check for Full Text / PubMed Unique Identifier (PMID): 17093111
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