Adaptive morphological changes of neocortical interneurons in response to enlarged and more complex pyramidal cells in p21H-RasVal12 transgenic mice

Alán Alpár, Gudrun Seeger, Wolfgang Härtig, Thomas Arendt, Ulrich Gärtner

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Morphological features of interneuronal adaptation to an altered, more complex neuronal architecture have been investigated in p21H-Ras Val12 transgenic mice. This transgenic strain serves as a model for studying the morphogenetic role of the G-protein p21Ras on cortical principal neurons. We have recently demonstrated that postmitotic expression of constitutively active p21H-RasVal12 in the neocortical pyramidal cell population results in increased size and dendritic complexity of the affected neurons, leading to an enlarged cortical volume. Interneurons do not express the transgene and are therefore excluded from direct, intrinsic p21H-RasVal12 effects. In the present study, immunolabelling of gamma-amino-butyric-acid (GABA), and of the calcium-binding proteins parvalbumin, calbindin and calretinin revealed that in the transgenic mice local circuit neurons are not increased in either somal size or number and their main morphological characteristics are preserved. However, the dendritic arbour of interneurons was found to be extended, at least in the vertical dimension, to follow the cortical expansion. Immunostaining for the vesicular GABA transporter revealed a denser inhibitory innervation of p21H-Ras Val12-expressing pyramidal cell perikarya than in those of wild-type animals, while the overall density of inhibitory axon terminals within the cortex was decreased in the transgenic animals as a consequence of cortical expansion. The findings of the present study demonstrate the morphogenetic capacity of interneurons for adapting to morphological alterations of principal neurons in the cerebral cortex.

Original languageEnglish
Pages (from-to)335-343
Number of pages9
JournalBrain Research Bulletin
Volume62
Issue number4
DOIs
Publication statusPublished - Jan 15 2004

Keywords

  • Cerebral cortex
  • G-protein
  • Plasticity

ASJC Scopus subject areas

  • Neuroscience(all)

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