2906292

Thiocyanate stabilizes AMPA binding to the quisqualate receptor.

Article date: 1988/11/22

PubMed ID: 2906292

Journal name: European journal of pharmacology (ISSN: 0014-2999)

ABSTRACT

Calcium and chloride ions stimulated [3H]glutamate binding to quisqualate-sensitive [3H]glutamate binding sites 4-fold, as measured by quantitative autoradiography, whereas 100 mM potassium thiocyanate had no additional effect. In contrast, calcium and chloride had little effect on the binding of [3H](RS)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid ([3H]AMPA), but 100 mM thiocyanate stimulated binding 4-fold. AMPA displaced little [3H]glutamate binding from quisqualate-sensitive binding sites in the molecular layer of the cerebellum in the absence of thiocyanate. However, in the presence of thiocyanate AMPA became a more effective displacer, but still displaced only 44% of the quisqualate-sensitive [3H]glutamate binding. The distribution of [3H]glutamate binding to quisqualate-sensitive sites was similar to but not identical with that of [3H]AMPA binding. However, the distribution of AMPA-displaceable [3H]glutamate binding correlated highly (r = 0.97, P less than 0.0005) with that of [3H]AMPA binding. The results suggest that AMPA binds to a subclass of quisqualate-sensitive [3H]glutamate binding sites that are highly influenced by ionic environment and that quisqualate-sensitive binding sites exist in several states.

Author List: Nielsen E O, Cha J H, Honoré T, Penney J B, Young A B

Publication Types: Journal Article; Research Support, U.S. Gov't, P.H.S.

Substances mentioned in the article: Chlorides; Coloring Agents; Glutamates; Ligands; Oxadiazoles; Oxazoles; Receptors, AMPA; Receptors, Glutamate; Receptors, Neurotransmitter; Thiocyanates; Ibotenic Acid; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; Calcium; potassium thiocyanate;

Mesh terms: Animals; Autoradiography; Brain/metabolism; Calcium/pharmacology; Chlorides/pharmacology; Coloring Agents/pharmacology; Glutamates; Ibotenic Acid/analogs & derivatives; Ligands; Male; Oxadiazoles; Oxazoles/metabolism; Rats; Rats, Inbred Strains; Receptors, AMPA; Receptors, Glutamate; Receptors, Neurotransmitter/analysis; Thiocyanates/pharmacology; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid;

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