Localization and source of γ aminobutyric acid immunoreactivity in the isthmic nucleus of the frog Rana esculenta

Edit Pollák, Gyula Lázár, Róbert Gábriel, Shou Rong Wang

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The distribution of γ-aminobutyric acid (GABA)-containing neurons and nerve fibers was studied in the isthmic nucleus of the frog Rana esculenta using light and electron microscopical immunohistochemical techniques. Approximately 0.5% of isthmic cells showed GABA immunopositivity, and the majority of these cells was found in the anterior one-third of the nucleus. A meshwork of GABA-immunostained fine beaded axons filled the entire isthmic nucleus. The GABA-immunoreactive terminals formed pericellular basket-like structures around a few cells both in the medulla and the cortex of the isthmic nucleus. To determine the source of GABA-positive fibers in the isthmic nucleus lesion experiments were carried out. After unilateral tectal ablation no change was observed in GABA immunoreactivity. Hemisectioning the tegmentum close to the anterior border of the isthmic nucleus, transection of the caudal rectal commissure and decussatio veli, or electrical lesioning of the anterodorsal tegmental nucleus all resulted in a moderate decrease in the density of GABA-positive fibers. Our results suggest that the majority of GABA-positive fibers derives from local GABA-positive cells, but some GABAergic afferents seem to arise in the tegmentum.

Original languageEnglish
Pages (from-to)343-350
Number of pages8
JournalBrain Research Bulletin
Volume48
Issue number3
DOIs
Publication statusPublished - Feb 1 1999

Keywords

  • Electron microscopy
  • Inhibitory interneurons
  • Synapses
  • Tegmental lesions

ASJC Scopus subject areas

  • Neuroscience(all)

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