Calretinin-containing interneurons innervate both principal cells and interneurons in the CA1 region of the human hippocampus

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Hippocampal interneurons consist of functionally diverse cell types, most of them target the dendrites or perisomatic region of pyramidal cells with a few exceptions, like the calretinin-containing cells in the rat: they selectively innervate other interneurons. However, no electron microscopic data are available about the synaptic connections of calretinin-immunoreactive neurons in the human hippocampus. We aimed to provide these data to establish whether interneuron-selective interneurons indeed represent an essential feature of hippocampal circuits across distant species. Two types of calretinin-immunostained terminals were found in the CA1 region: one of them presumably derived from the thalamic reuniens nucleus, and established asymmetric synapses on dendrites and spines. The other type originating from local interneurons formed symmetric synapses on both pyramidal and interneuron dendrites. Distribution of postsynaptic targets showed that 26.8% of the targets were CR-positive interneuron dendrites, and 25.2% proved to be proximal pyramidal dendrites. CR-negative interneuron dendrites were also contacted (12.4%). Small caliber postsynaptic dendrites were not classified (28%). Somata were rarely contacted (7.6%). The present data suggest that calretinin-positive boutons do show a preference for other interneurons, but a considerable proportion of the targets are pyramidal cells. We propose that interneuron-selective inhibitory cells exist in the human Ammon's horn, and boutons innervating pyramidal cells derive from another cell type that might not exist in rodents.

Original languageEnglish
Pages (from-to)205-220
Number of pages16
JournalActa Biologica Hungarica
Volume53
Issue number1-2
DOIs
Publication statusPublished - 2002

Fingerprint

Calbindin 2
interneurons
Interneurons
hippocampus
Hippocampus
dendrites
Dendrites
cells
Pyramidal Cells
rodent
Carisoprodol
Neurons
Rats
electron
synapse
Synapses
Midline Thalamic Nuclei
Electrons
Networks (circuits)
spine (bones)

Keywords

  • Calcium binding proteins
  • Electron microscopy
  • Interneuron selective cell
  • Postsynaptic targets
  • Species differences

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)

Cite this

@article{adcec5467bf6413daf2bbdc1a3e6be92,
title = "Calretinin-containing interneurons innervate both principal cells and interneurons in the CA1 region of the human hippocampus",
abstract = "Hippocampal interneurons consist of functionally diverse cell types, most of them target the dendrites or perisomatic region of pyramidal cells with a few exceptions, like the calretinin-containing cells in the rat: they selectively innervate other interneurons. However, no electron microscopic data are available about the synaptic connections of calretinin-immunoreactive neurons in the human hippocampus. We aimed to provide these data to establish whether interneuron-selective interneurons indeed represent an essential feature of hippocampal circuits across distant species. Two types of calretinin-immunostained terminals were found in the CA1 region: one of them presumably derived from the thalamic reuniens nucleus, and established asymmetric synapses on dendrites and spines. The other type originating from local interneurons formed symmetric synapses on both pyramidal and interneuron dendrites. Distribution of postsynaptic targets showed that 26.8{\%} of the targets were CR-positive interneuron dendrites, and 25.2{\%} proved to be proximal pyramidal dendrites. CR-negative interneuron dendrites were also contacted (12.4{\%}). Small caliber postsynaptic dendrites were not classified (28{\%}). Somata were rarely contacted (7.6{\%}). The present data suggest that calretinin-positive boutons do show a preference for other interneurons, but a considerable proportion of the targets are pyramidal cells. We propose that interneuron-selective inhibitory cells exist in the human Ammon's horn, and boutons innervating pyramidal cells derive from another cell type that might not exist in rodents.",
keywords = "Calcium binding proteins, Electron microscopy, Interneuron selective cell, Postsynaptic targets, Species differences",
author = "Z. Urb{\'a}n and Z. Magl{\'o}czky and T. Freund",
year = "2002",
doi = "10.1556/ABiol.53.2002.1-2.19",
language = "English",
volume = "53",
pages = "205--220",
journal = "Acta Biologica Hungarica",
issn = "0236-5383",
publisher = "Akademiai Kiado",
number = "1-2",

}

TY - JOUR

T1 - Calretinin-containing interneurons innervate both principal cells and interneurons in the CA1 region of the human hippocampus

AU - Urbán, Z.

AU - Maglóczky, Z.

AU - Freund, T.

PY - 2002

Y1 - 2002

N2 - Hippocampal interneurons consist of functionally diverse cell types, most of them target the dendrites or perisomatic region of pyramidal cells with a few exceptions, like the calretinin-containing cells in the rat: they selectively innervate other interneurons. However, no electron microscopic data are available about the synaptic connections of calretinin-immunoreactive neurons in the human hippocampus. We aimed to provide these data to establish whether interneuron-selective interneurons indeed represent an essential feature of hippocampal circuits across distant species. Two types of calretinin-immunostained terminals were found in the CA1 region: one of them presumably derived from the thalamic reuniens nucleus, and established asymmetric synapses on dendrites and spines. The other type originating from local interneurons formed symmetric synapses on both pyramidal and interneuron dendrites. Distribution of postsynaptic targets showed that 26.8% of the targets were CR-positive interneuron dendrites, and 25.2% proved to be proximal pyramidal dendrites. CR-negative interneuron dendrites were also contacted (12.4%). Small caliber postsynaptic dendrites were not classified (28%). Somata were rarely contacted (7.6%). The present data suggest that calretinin-positive boutons do show a preference for other interneurons, but a considerable proportion of the targets are pyramidal cells. We propose that interneuron-selective inhibitory cells exist in the human Ammon's horn, and boutons innervating pyramidal cells derive from another cell type that might not exist in rodents.

AB - Hippocampal interneurons consist of functionally diverse cell types, most of them target the dendrites or perisomatic region of pyramidal cells with a few exceptions, like the calretinin-containing cells in the rat: they selectively innervate other interneurons. However, no electron microscopic data are available about the synaptic connections of calretinin-immunoreactive neurons in the human hippocampus. We aimed to provide these data to establish whether interneuron-selective interneurons indeed represent an essential feature of hippocampal circuits across distant species. Two types of calretinin-immunostained terminals were found in the CA1 region: one of them presumably derived from the thalamic reuniens nucleus, and established asymmetric synapses on dendrites and spines. The other type originating from local interneurons formed symmetric synapses on both pyramidal and interneuron dendrites. Distribution of postsynaptic targets showed that 26.8% of the targets were CR-positive interneuron dendrites, and 25.2% proved to be proximal pyramidal dendrites. CR-negative interneuron dendrites were also contacted (12.4%). Small caliber postsynaptic dendrites were not classified (28%). Somata were rarely contacted (7.6%). The present data suggest that calretinin-positive boutons do show a preference for other interneurons, but a considerable proportion of the targets are pyramidal cells. We propose that interneuron-selective inhibitory cells exist in the human Ammon's horn, and boutons innervating pyramidal cells derive from another cell type that might not exist in rodents.

KW - Calcium binding proteins

KW - Electron microscopy

KW - Interneuron selective cell

KW - Postsynaptic targets

KW - Species differences

UR - http://www.scopus.com/inward/record.url?scp=0036010817&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036010817&partnerID=8YFLogxK

U2 - 10.1556/ABiol.53.2002.1-2.19

DO - 10.1556/ABiol.53.2002.1-2.19

M3 - Article

C2 - 12064772

AN - SCOPUS:0036010817

VL - 53

SP - 205

EP - 220

JO - Acta Biologica Hungarica

JF - Acta Biologica Hungarica

SN - 0236-5383

IS - 1-2

ER -