[High-voltage electron microscopic observations on mouse olfactory bulb neurons].

Area of Science:

• Neuroscience
• Cell Biology
• Microscopy

Context:

• The mouse olfactory bulb is a critical brain region for processing olfactory information.
• Understanding the fine structure of olfactory bulb neurons is essential for deciphering olfactory processing mechanisms.
• Previous studies using light microscopy provided limited resolution of these complex neuronal structures.

Purpose:

• To investigate the fine structures of Golgi-impregnated mitral, tufted, and granule cells in the mouse olfactory bulb.
• To compare the observational capabilities of high-voltage electron microscopy (HVEM) with light microscopy for neuronal morphology.
• To precisely characterize intraglomerular dendritic trees and granule cell spines.

Summary:

• High-voltage electron microscopy enabled precise observation of intraglomerular dendritic tufts of mitral and tufted cells, revealing varicose branches with a 'thread and beads' appearance and spine-like appendages.
• Granule cell spines were individually resolved, even when clustered, with terminal swelling widths varying by location (granule cell layer vs. mitral body/external plexiform layer).
• HVEM significantly enhanced the recognition of neuronal spines compared to light microscopy, providing greater detail on their morphology and distribution.

Impact:

• Provides unprecedented high-resolution morphological data of key olfactory bulb neuronal components.
• Offers a deeper understanding of the structural basis for synaptic integration within the olfactory bulb.
• Highlights the utility of HVEM for detailed ultrastructural analysis in neuroscience research.