Quisqualate-induced changes in extracellular sodium and calcium concentrations persist in the combined presence of NMDA and non-NMDA receptor antagonists in rat hippocampal slices.

Article date: 1990/8/14

PubMed ID: 1979665

Journal name: Neuroscience letters (ISSN: 0304-3940)


In the CA1 stratum pyramidale of rat hippocampal slices we have used Ca2(+)- and Na(+)-sensitive microelectrodes to measure the changes in [Ca2+]o, [Na+]o and associated slow field potentials elicited by the iontophoretic application of the excitatory amino acids N-methyl-D-aspartic acid (NMDA), quisqualic acid (Quis), alpha-amino-3-hydroxy-5-methyl-4-isoazolepropionic acid (AMPA) and glutamic acid (Glu) in the presence of the NMDA receptor antagonists 2-amino-5-phosphonovaleric acid (AP5) and ketamine and the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). Although a combination of these antagonists blocked stimulation-induced synaptic field potentials as well as AMPA- and NMDA-induced ionic changes and associated field potentials, Quis-induced ionic changes and associated field potentials could still be observed after 60 min. These residual Quis signals were also resistant to 2-amino-3-phosphonopropionic acid (AP3) and 2-amino-4-phosphonobutyric acid (AP4) suggesting that metabotropic receptors do not play a role in the generation of these signals. We suggest that the receptor class activated under these conditions may play a role in CNQX/AP5-resistant epileptogenesis as well as other pathophysiological conditions.

This document is available from: http://directlinks.cc/files/muscimol/1979665.pdf

Author List: Mudrick L A, Heinemann U

Publication Types: Journal Article; Research Support, Non-U.S. Gov't

Substances mentioned in the article: Glutamates; Quinoxalines; Receptors, N-Methyl-D-Aspartate; Ibotenic Acid; Glutamic Acid; N-Methylaspartate; Ketamine; 6-Cyano-7-nitroquinoxaline-2,3-dione; 2-Amino-5-phosphonovalerate; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; Quisqualic Acid; Sodium; Calcium;

Mesh terms: 2-Amino-5-phosphonovalerate/pharmacology; 6-Cyano-7-nitroquinoxaline-2,3-dione; Animals; Calcium/metabolism; Evoked Potentials/drug effects; Extracellular Space/drug effects; Glutamates/pharmacology; Glutamic Acid; Hippocampus/drug effects; Ibotenic Acid/analogs & derivatives; In Vitro Techniques; Ketamine/pharmacology; Membrane Potentials/drug effects; N-Methylaspartate/pharmacology; Quinoxalines/pharmacology; Quisqualic Acid/pharmacology; Rats; Receptors, N-Methyl-D-Aspartate/drug effects; Sodium/metabolism; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid;

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