An investigation into signal transduction mechanisms involved in insulin-induced long-term depression in the CA1 region of the hippocampus

Chiung Chun Huang, Cheng Che Lee, Kuei Sen Hsu

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83 Citations (Scopus)

Abstract

Recent work has demonstrated that brief application of insulin to hippocampal slices can induce a novel form of long-term depression (insulin-LTD) in the CA1 region of the hippocampus; however, the molecular details of how insulin triggers LTD remain unclear. Using electrophysiological and biochemical approaches in the hippocampal slices, we show here that insulin-LTD (i) is specific to 3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor- but not NMDA receptor-mediated synaptic transmission; (ii) is induced and expressed postsynaptically but does not require the activation of ionotropic and metabotropic glutamate receptors; (iii) requires a concomitant Ca2+ influx through L-type voltage-activated Ca2+ channels (VACCs) and the release of Ca2+ from intracellular stores; (iv) requires the series of protein kinases, including protein tyrosine kinase (PTK), phosphatidylinositol 3-kinase (PI3K), and protein kinase C (PKC); (v) is mechanistically distinct from low-frequency stimulation-induced LTD (LFS-LTD) and independent on protein phosphatase 1/2 A (PP1/2 A) and PP2B activation; (vi) is dependent on a rapamycin-sensitive local translation of dendritic m RNA, and (vii) is associated with a persistent decrease in the surface expression of GluR2 subunit. These results suggest that a PI3K/PKC-dependent insulin signaling, which controls postsynaptic surface AMPA receptor numbers through PP-independent endocytosis, may be a major expression mechanism of insulin-LTD in hippocampal CA1 neurons.

Original languageEnglish
Pages (from-to)217-231
Number of pages15
JournalJournal of Neurochemistry
Volume89
Issue number1
DOIs
Publication statusPublished - 2004 Apr

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Cellular and Molecular Neuroscience

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