Leptin induces a novel form of NMDA receptor-dependent long-term depression

Murat Durakoglugil, Andrew J. Irving, Jenni Harvey

Research output: Contribution to journalArticle

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Abstract

It is becoming apparent that the hormone leptin plays an important role in modulating hippocampal function. Indeed, leptin enhances NMDA receptor activation and promotes hippocampal long-term potentiation (LTP). Furthermore, obese rodents with dysfunctional leptin receptors display impairments in hippocampal synaptic plasticity. Here we demonstrate that under conditions of enhanced excitability (evoked in Mg2+-free medium or following blockade of GABAA receptors), leptin induces a novel form of long-term depression (LTD) in area CA1 of the hippocampus. Leptin-induced LTD was markedly attenuated in the presence of D-(-)-2-Amino-5-Phosphonopentanoic acid (D-AP5), suggesting that it is dependent on the synaptic activation of NMDA receptors. In addition, low-frequency stimulus-evoked LTD occluded the effects of leptin. In contrast, metabotropic glutamate receptors (mGluRs) did not contribute to leptin-induced LTD as mGluR antagonists failed to either prevent or reverse this process. The signalling mechanisms underlying leptin-induced LTD were independent of the Ras-Raf-mitogen-activated protein kinase signalling pathway, but were markedly enhanced following inhibition of either phosphoinositide 3-kinase or protein phosphatases 1 and 2A. These data indicate that under conditions of enhanced excitability, leptin induces a novel form of homosynaptic LTD, which further underscores the proposed key role for this hormone in modulating NMDA receptor-dependent hippocampal synaptic plasticity.

Original languageEnglish (US)
Pages (from-to)396-405
Number of pages10
JournalJournal of Neurochemistry
Volume95
Issue number2
DOIs
Publication statusPublished - Oct 2005

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Keywords

  • Hippocampus
  • Leptin
  • Long-term depression
  • NMDA receptor-dependent

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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