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Updated: Jun 25, 2026
18:11
Quantifying Synapses: an Immunocytochemistry-based Assay to Quantify Synapse Number
Published on: November 16, 2010
Multiple synapse formation: a possible compensatory mechanism for increased cell size in rat supraoptic nucleus
1Department of Psychology and Neuroscience Program, Michigan State University, East Lansing, Michigan 48824-1117, USA.
Journal of Neuroendocrinology
|February 13, 2009
Summary
Chronic dehydration causes rat supraoptic nucleus cells to enlarge and form more multiple synapses. This synapse formation may compensate for increased cell size, enhancing neuronal activation during dehydration.
Area of Science:
- Neuroscience
- Cell Biology
- Physiology
Background:
- Magnocellular neuroendocrine cells in the rat supraoptic nucleus exhibit morphological changes during chronic dehydration.
- Previous studies on synapse formation did not account for somatic size changes, limiting understanding of compensatory mechanisms.
Purpose of the Study:
- To investigate if multiple synapse formation compensates for increased somatic size in dehydrated rats.
- To quantify changes in single and multiple synapses, membrane apposition, and glial coverage.
Main Methods:
- Morphometric analysis of supraoptic nucleus cells from chronically dehydrated and well-hydrated rats.
- Stereological estimation of synapse numbers per unit area and somatic surface area.
- Measurement of somatic membrane apposition and glial coverage.
Main Results:
- Somatic surface area increased by over 70% in dehydrated animals.
- The percentage of somatic membrane contacted by multiple synapses doubled, while single synapses decreased by 41%.
- Dehydrated rats showed significantly more multiple synapses per soma (23 vs. 6) and increased direct neuronal apposition.
Conclusions:
- Multiple synapse formation partially compensates for decreased synaptic density due to cell enlargement during dehydration.
- Altered synaptic input and increased neuronal apposition likely enhance supraoptic nucleus activation during dehydration.
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