1846403

Comparison of solubilised kainate and alpha-amino-3-hydroxy-5- methylisoxazolepropionate binding sites in chick cerebellum.

Article date: 1991/2/1

PubMed ID: 1846403

Journal name: Journal of neurochemistry (ISSN: 0022-3042)

ABSTRACT

[3H]Kainate bound to chick cerebellar membranes with a KD of 0.6 microM and with an exceptionally high Bmax of 165 pmol/mg of protein. In octylglucoside-solubilised extracts, the affinity of [3H]kainate was reduced (KD = 2.7 microM), but the Bmax was relatively unchanged (130 pmol/mg of protein). The rank potency of competitive ligands was domoate greater than kainate greater than 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) greater than glutamate. Binding sites for alpha-[3H]amino-3- hydroxy-5-methylisoxazolepropionate ([3H]AMPA) were much less abundant, with KD and Bmax values in membranes of 86 nM and 1 pmol/mg of protein, respectively. The affinity of [3H]AMPA binding was also reduced on solubilisation (KD = 465 nM), but there was an increase in the Bmax (1.7 pmol/mg of protein). Quisqualate and CNQX were the most effective displacers of [3H]AMPA binding, but kainate was also a relatively potent inhibitor. However, in contrast to the displacement profile for [3H]kainate, domoate was markedly less potent than kainate at displacing [3H]AMPA. These results suggest that [3H]AMPA binds to a small subset of the kainate sites that, unlike the majority of the [3H]kainate binding protein, which has been reported to be located in the Bergmann glia, may represent neuronal unitary non-N-methyl-D-aspartate receptors.

Author List: Henley J M, Barnard E A

Publication Types: Comparative Study; Journal Article

Substances mentioned in the article: Glucosides; Receptors, AMPA; Receptors, Kainic Acid; Receptors, Neurotransmitter; Ibotenic Acid; octyl-beta-D-glucoside; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; domoic acid; Kainic Acid;

Mesh terms: Animals; Binding, Competitive; Cell Membrane/metabolism; Cerebellum/metabolism; Chickens; Glucosides; Ibotenic Acid/analogs & derivatives; Kainic Acid/analogs & derivatives; Receptors, AMPA; Receptors, Kainic Acid; Receptors, Neurotransmitter/metabolism; Solubility; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid;

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