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Updated: Aug 29, 2026

High-Resolution Quantitative Immunogold Analysis of Membrane Receptors at Retinal Ribbon Synapses
Published on: February 18, 2016
Presynaptic NMDA receptors in the neocortex are both auto- and heteroreceptors
S DeBiasi1, A Minelli, M Melone
1Department of General Physiology and Biochemistry, University of Milan, Italy.
Abstract:
We used electron microscopic immunocytochemistry with antibodies against NR1 and NR2A and B subunits to study the distribution of N-methyl-D-aspartate (NMDA) receptors in presynaptic axon terminals in the rat cerebral cortex. In all sections examined, NR1 and NR2A/B immunoreactivities were observed in axon terminals: NR1- and NR2A/B-positive axon terminals made both symmetrical and asymmetrical synapses on unlabelled dendritic profiles. Combined pre- and postembedding studies showed that all NR1 and NR2A/B-positive axon terminals making symmetrical synapses were gamma-aminobutyric acid (GABA)-positive. These observations show that both auto- and hetero- NMDA receptors do exist in the cerebral cortex, and indicate that part of the effects of NMDA receptor activation might be determined by modulating glutamate and GABA release.
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