Hippocampal CA3 pyramidal cells selectively innervate aspiny interneurons

Lucia Wittner, Darrell A. Henze, László Záborszky, György Buzsáki

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

The specific connectivity among principal cells and interneurons determines the flow of activity in neuronal networks. To elucidate the connections between hippocampal principal cells and various classes of interneurons, CA3 pyramidal cells were intracellularly labelled with biocytin in anaesthetized rats and the three-dimensional distribution of their axon collaterals was reconstructed. The sections were double-stained for substance P receptor (SPR)- or metabotropic glutamate receptor 1α (mGluR-1α)-immunoreactivity to investigate interneuron targets of the CA3 pyramidal cells. SPR-containing interneurons represent a large portion of the GABAergic population, including spiny and aspiny classes. Axon terminals of CA3 pyramidal cells contacted SPR-positive interneuron dendrites in the hilus and in all hippocampal strata in both CA3 and CA1 regions (7.16% of all boutons). The majority of axons formed single contacts (87.5%), but multiple contacts (up to six) on single target neurons were also found. CA3 pyramidal cell axon collaterals innervated several types of morphologically different aspiny SPR-positive interneurons. In contrast, spiny SPR-interneurons or mGluR-1α-positive interneurons in the hilus, CA3 and CA1 regions were rarely contacted by the filled pyramidal cells. These findings indicate a strong target selection of CA3 pyramidal cells favouring the activation of aspiny classes of interneurons.

Original languageEnglish (US)
Pages (from-to)1286-1298
Number of pages13
JournalEuropean Journal of Neuroscience
Volume24
Issue number5
DOIs
StatePublished - Sep 2006

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)

Keywords

  • Connectivity
  • Metabotropic glutamate receptor-1α
  • Selective targeting
  • Substance P receptor

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