Metabotropic glutamate receptors modulate GABA release from mouse hippocampal slices.
The effects of metabotropic glutamate receptor agonists on the basal and potassium (50 mM K+)-stimulated release of [3H]GABA from mouse hippocampal slices were investigated using a superfusion system. The group I agonist (1+/-)-1-aminocyclopentane-trans-1,3-dicarboxylate enhanced the basal GABA release and reduced the K+-evoked release by a mechanism antagonized by (RS)-1-aminoindan-1,5-dicarboxylate in both cases. The group II agonist (2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine failed to have any effect on the basal release, but inhibited the stimulated release. This inhibition was not affected by the antagonist (2S)-2-ethylglutamate. The group III agonists L(+)-amino-4-phosphonobutyrate and O-phospho-L-serine inhibited the basal GABA release, which effects were blocked by the antagonist (RS)-2-cyclopropyl-4-phosphonophenylglycine. Moreover, the suppression of the K+-evoked release by L(+)2-amino-4-phosphonobutyrate was apparently receptor-mediated, being blocked by (RS)-2-cyclopropyl-4-phosphonophenylglycine. The results show that activation of metabotropic glutamate receptors of group I is able to potentiate the basal release of GABA, whereas activation of groups I and III receptors reduce K+-stimulated release in mouse hippocampal slices.
Saransaari
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Tampere Brain Research Center, Medical School, University of Tampere, Finland. blpisa@uta.fi
Oja
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SS
D000818:Animals; D005260:Female; D006624:Hippocampus / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D018094:Receptors, Metabotropic Glutamate; D005680:gamma-Aminobutyric Acid