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Present status of paraneuron concept
1Department of Anatomy, Niigata University School of Medicine, Japan.
Archives of Histology and Cytology
|January 1, 1989
Summary
Paraneurons are specialized cells that secrete substances like neurons, identified by specific granules. While chromogranins are key markers, some cells producing similar substances lack them, blurring classification lines.
Area of Science:
- Neuroscience
- Cell Biology
- Endocrinology
Background:
- Paraneurons are receptosecretory cells sharing characteristics with neurons, such as containing bioactive substances in membrane-bound granules.
- These granules contain peptides, amines, nucleotides, and acidic carrier proteins, notably chromogranins.
Purpose of the Study:
- To emphasize the cell-biological significance of carrier proteins within secretory granules.
- To highlight the utility of immunohistochemical detection of chromogranins as reliable paraneuron markers.
- To discuss the unclear boundaries between neurons and paraneurons due to gradational spectra of cell types.
Main Methods:
- Review of cell-biological and immunohistochemical literature on paraneurons.
- Analysis of chromogranin immunoreactivity in various cell types.
Main Results:
- Chromogranins serve as reliable markers for typical paraneurons.
- Cells ectopically producing bioactive peptides/amines (e.g., cardiac muscle cells) often lack chromogranin immunoreactivity.
- The classification of cells like mast cells within the paraneuron category is debatable, with an epithelial definition proposed.
Conclusions:
- Chromogranin detection is crucial for identifying paraneurons.
- The definition and boundaries of paraneurons require careful consideration due to cellular heterogeneity.
- An epithelial nature is suggested as a defining characteristic for paraneurons.