Predominant expression of group-II metabotropic glutamate receptors in the goldfish brain.
Group-II metabotropic glutamate (mGlu) receptors (mGlu2/3 receptors) were highly expressed in various regions (telencephalon, optic tectum, and cerebellum, but not vagal lobe) of the goldfish brain. In the goldfish telencephalon, expression of mGlu2/3 receptors was even higher than in the rat cerebral cortex. In contrast, mGlu5 receptors showed low levels of expression in all goldfish brain regions, whereas mGlu1a receptors were only expressed in the goldfish cerebellum. Pharmacological activation of group-II mGlu receptors with the selective agonists, 2R,4R-4-aminopyrrolidine-2, 4-dicarboxylic acid and (2S,2'R,3'R)-2-(2,3-dicarboxycyclopropyl) glycine, reduced the evoked release of glutamate from goldfish brain synaptosomes, whereas agonists of group-I and -III mGlu receptors (3, 5-dihydroxyphenylglycine and L-2-amino-4-phosphonobutanoate) were inactive. The predominance of group-II over group-I mGlu receptors in the goldfish brain may provide a natural defense against excitotoxic neuronal death and contribute to the unusually high resistance of goldfish against hypoxic brain damage.
Department of Biology, University of Bologna, Bologna, Italy.
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Poli
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Lucchi
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Storto
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De Paolis
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Notari
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Nicoletti
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Casabona
D000818:Animals; D001921:Brain / Q000378:metabolism*; D003521:Cyclopropanes / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D006054:Goldfish / Q000378:metabolism*; D008297:Male; D011392:Proline / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists / Q000378:metabolism*; D014018:Tissue Distribution / Q000502:physiology
C097299:4-aminopyrrolidine-2,4-dicarboxylic acid; D003521:Cyclopropanes; D018690:Excitatory Amino Acid Agonists; D018094:Receptors, Metabotropic Glutamate; C108822:metabotropic glutamate receptor 2; C102718:metabotropic glutamate receptor 3; C082313:2-(2,3-dicarboxycyclopropyl)glycine; D018698:Glutamic Acid; D011392:Proline; D005998:Glycine