Enhanced Sensitivity of “Metabotropic” Glutamate Receptors After Induction of Long‐Term Potentiation in Rat Hippocampus

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

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


Stimulation of [3H]inositol monophosphate <[3H]InsP) formation by ibotenate or trans‐1‐aminocyclopentyl‐l, 3‐dicarboxylic acid (t‐ACPD) in rat hippocampal slices was enhanced after tetanic stimulation of die Schaffer collaterals projecting to the CA1 region (in vitro) or the perforant pathway projecting to the dentate gyms (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.

Original languageEnglish (US)
Pages (from-to)376-383
Number of pages8
JournalJournal of Neurochemistry
Issue number2
StatePublished - Aug 1991
Externally publishedYes


  • Glutamate
  • Hippocampus
  • Long‐term potentiation
  • Phosphoinositides

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience


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