Electron microscopic data on the neurons of nuclei subpretectalis and posterior-ventralis thalami. A combined immunohistochemical study

T. Tömböl, A. Németh, T. Sebestény, A. Alpár

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

The nucleus rotundus receives GABA-like immunoreactive fibres from the nuclei subpretectalis and postero-ventralis thalami. This result was confirmed by Phaseolus vulgaris leucoagglutinin (phA-L) anterograde tracer and with electron microscopic (EM) γ-aminobutiric acid (GABA)-immunogold staining. The detailed electron microscopic analysis of the structure of the neurons in these nuclei revealed that the neurons in the nucleus subpretectalis displayed GABA-like immunoreactivity. In the postero-ventral thalamic nucleus a group of neurons was GABA-positive. The surface of the neurons was covered both with numerous GABA-negative and GABA-like immunoreactive terminals that established asymmetrical and symmetrical synapses, respectively, with the GABA-positive neurons. The GABA-like immunonegative terminals are supposed to be the axon terminals of the collaterals of tecto-rotundal fibres in the subpretectal nucleus and the collateral terminal branches of contralateral tecto-rotundal fibres in the postero-ventralis thalami. In both nuclei, the GABA-like immunoreactive terminals may be developed by the collaterals of local neurons that establish symmetrical synapses. In the Phaseolus lectin-stained preparations these terminals may be labelled. The morphological characteristics of the neurons in the subpretectal and partly, in the postero-ventral nuclei are similar to those of interneurons (local circuit neurons) and the numerous asymmetrical and symmetrical axo-somatic synapses, respectively. But these neurons locate outside of their target nucleus, and exert their modulatory effect on rotundo-ectostriatal transmission. Also, a contralateral influence is present in the nucleus rotundus that may interact in the cooperation of the eyes. The neurons of the subpretectal and postero-ventral nuclei, similarly to the neurons of isthmic nuclei, are a special group of modulatory neurons with effects at a distance.

Original languageEnglish
Pages (from-to)169-183
Number of pages15
JournalAnatomy and Embryology
Volume199
Issue number2
DOIs
Publication statusPublished - Mar 27 1999

Keywords

  • Modulatory neurons
  • Nuclei subpretectalis
  • Postero-ventralis thalami

ASJC Scopus subject areas

  • Anatomy
  • Embryology
  • Developmental Biology
  • Cell Biology

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