Enhanced sensitivity of "metabotropic" glutamate receptors after induction of long-term potentiation in rat hippocampus.

Article date: 1991/8/1

PubMed ID: 1649248

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


Stimulation of [3H]inositol monophosphate ([3H]InsP) formation by ibotenate or trans-1-aminocyclopentyl-1,3-dicarboxylic acid (t-ACPD) in rat hippocampal slices was enhanced after tetanic stimulation of the Schaffer collaterals projecting to the CA1 region (in vitro) or the perforant pathway projecting to the dentate gyrus (in freely moving animals). This effect was observed 5 h (but not 2 h) after long-term potentiation (LTP) induction and was abolished if tetanic stimulation was performed in the presence of specific antagonists of N-methyl-D-aspartate receptors. The delayed increase in excitatory amino acid-induced polyphosphoinositide (PPI) hydrolysis was accompanied by an enhanced responsiveness to norepinephrine, whereas the basal and carbamylcholine-stimulated [3H]InsP formation were unchanged. These results suggest that an increased activity of “metabotropic” glutamate receptors may contribute to the synaptic mechanisms enabling the late expression and or maintenance of LTP. Accordingly, LTP decayed more rapidly (within 5 h) in rats repeatedly injected with LiCl (60-120 mg/kg, i.p., for 10 days), a treatment that led to a reduced efficacy of ibotenate and norepinephrine in stimulating PPI hydrolysis in hippocampal slices.

Author List: Aronica E, Frey U, Wagner M, Schroeder H, Krug M, Ruthrich H, Catania M V, Nicoletti F, Reymann K G

Publication Types: Journal Article

Substances mentioned in the article: Chlorides; Glutamates; Phosphatidylinositol Phosphates; Phosphatidylinositols; Receptors, Glutamate; Receptors, Neurotransmitter; Ibotenic Acid; Lithium; Lithium Chloride; Norepinephrine;

Mesh terms: Animals; Chlorides/pharmacology; Electric Stimulation; Evoked Potentials; Glutamates/metabolism; Hippocampus/drug effects; Ibotenic Acid/pharmacology; In Vitro Techniques; Kinetics; Lithium/pharmacology; Lithium Chloride; Male; Norepinephrine/pharmacology; Phosphatidylinositol Phosphates; Phosphatidylinositols/metabolism; Rats; Rats, Inbred Strains; Receptors, Glutamate; Receptors, Neurotransmitter/drug effects; Time Factors;

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