Excitatory amino acids: new tools for old stories or pharmacological subtypes of glutamate receptors: electrophysiological studies.

Article date: 1991/7/1

PubMed ID: 1659489

Journal name: Canadian journal of physiology and pharmacology (ISSN: 0008-4212)


Although the N-methyl-D-aspartate (NMDA) subtype of L-glutamate receptor is well characterized, the significance of non-NMDA glutamate-sensitive binding sites is not well documented. In this study, a new tricyclic quinoxalinedione (NBQX) and an arthropod toxin (philanthotoxin) were shown to block responses of spinal neurones in vivo to kainate, quisqualate, and AMPA in parallel but had little effect on responses to NMDA. Philanthotoxin appeared to be a use-dependent antagonist consistent with a channel-blocking mode of action. On cortical wedges in vitro, however, NBQX proved to be a more potent antagonist of AMPA and quisqualate than of kainate (pA2 values of 7.1, 7.0, and 5.6, respectively) with no effect at 10 microM on responses to NMDA. These studies provide evidence that on cortical neurones, but not on spinal neurones. AMPA and kainate depolarize by pharmacologically different mechanisms.

Author List: Lodge D, Jones M G, Palmer A J

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

Substances mentioned in the article: Amino Acids; Polyamines; Quinoxalines; Receptors, Glutamate; Receptors, Neurotransmitter; Wasp Venoms; Ibotenic Acid; N-Methylaspartate; delta-philanthotoxin; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; Quisqualic Acid; Kainic Acid;

Mesh terms: Amino Acids/physiology; Animals; Brain Stem/cytology; Cerebral Cortex/cytology; Electrophysiology; Ibotenic Acid/analogs & derivatives; In Vitro Techniques; Kainic Acid/pharmacology; N-Methylaspartate/pharmacology; Neurons/drug effects; Polyamines; Quinoxalines/pharmacology; Quisqualic Acid/pharmacology; Rats; Receptors, Glutamate; Receptors, Neurotransmitter/drug effects; Spinal Cord/cytology; Wasp Venoms/pharmacology; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid;

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