Ciliated neurons and different types of synapses in anterior hypothalamic nuclei of reptiles

I. Vigh-Teichmann, B. Vigh, B. Aros

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

The magnocellular paraventricular and supraoptic nuclei and the parvocellular preoptic and periventricular nuclei have been studied by light and electron microscopy in Emys orbicularis, Lacerta agilis and Elaphe longissima. The ultrastructure of cerebrospinal fluid (CSF)-contacting neurons was described in the preoptic and periventricular nuclei of Emys and Lacerta species. Single 9×2+0 cilia similar to those of the CSF-contacting dendritic terminals were found on perikarya of non CSF-contacting nerve cells, in all four investigated nuclei. The cilia project from funnel-like invaginations of the perikarya into the intercellular space. In the neurons of the nuclei studied, granular vesicles were found, their size being mainly 1,600 Å in the paraventricular nucleus, about 1,800 Å in the supraoptic nucleus, 1,100 Å in the periventricular nucleus and 800 Å, or up to 1,250 Å in the preoptic nucleus. In general, the neurons possess synapses of the axo-somatic, axo-somatic spine, axo-dendritic and axo-dendritic spine types. In the supraoptic nucleus, multiple interdigitated synapses were observed. Presynaptically, either synaptic vesicles only, or synaptic vesicles and dense core vesicles of different sizes (600 to 800 Å, about 1,100 Å, 1250 Å, and up to 2,000 Å) were found. It is discussed whether the above described 9×2+0 cilia may represent some kind of hypothalamic sensory structure that earlier physiological studies postulated to exist. The ciliated hypothalamic perikarya are considered by the authors to be a more differentiated form of the CSF-contacting neurons. The different types of synapses indicate multilateral connections of the nerve cells of the nuclei studied.

Original languageEnglish
Pages (from-to)139-160
Number of pages22
JournalCell And Tissue Research
Volume174
Issue number1
DOIs
Publication statusPublished - Oct 1 1976

Keywords

  • Cerebrospinal fluid-contacting neurons
  • Ciliated perikarya
  • Neurosecretory nuclei
  • Reptile hypothalamus
  • Synapses

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology
  • Cell Biology

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