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Published on: September 5, 2018
Distribution and densitometry mapping of L1-CAM immunoreactivity in the adult mouse brain--light microscopic
Hana Munakata1, Yukiko Nakamura, Kazumasa Matsumoto-Miyai
1Division of Structural Cell Biology, Nara Institute of Science and Technology, NAIST, 8916-5 Takayama, Ikoma city, Nara 630-0192, Japan. munktahn@banyu.co.jp
Insights
Neural cell adhesion molecule L1 (L1) is widely distributed in the adult mouse brain, with varying levels in both neuronal and non-neuronal elements. This distribution pattern provides insights into L1
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Biology
Background:
- Neural cell adhesion molecule L1 (L1) expression is crucial in the mature brain.
- Studies link L1 to hippocampal plasticity and fear conditioning.
- Understanding L1 distribution aids in elucidating its brain functions.
Purpose of the Study:
- To map the distribution of L1 in the adult mouse brain.
- To identify neuronal and non-neuronal elements expressing L1.
- To correlate L1 expression patterns with brain structures.
Main Methods:
- Immunohistochemistry using two polyclonal antibodies against L1.
- Examination of L1 distribution across the entire adult mouse brain.
- Analysis of L1 immunoreactivity in various brain regions and cell types.
Main Results:
- L1 was widely and unevenly distributed from the olfactory bulb to the upper cervical cord.
- Highest L1 accumulation occurred in non-neuronal elements of major fiber bundles.
- Significant L1 levels were observed in grey matter, including specific cortical and subcortical regions, with lower levels in the hippocampus and thalamus.
Conclusions:
- L1 exhibits a broad and heterogeneous distribution in the mature mouse brain.
- L1 immunoreactivity is found in both neuronal (axons, synapses, cell soma) and non-neuronal elements.
- The diverse localization of L1 suggests multifaceted roles in brain function.
Background:
The importance of L1 expression in the matured brain is suggested by physiological and behavioral studies showing that L1 is related to hippocampal plasticity and fear conditioning. The distribution of L1 in mouse brain might provide a basis for understanding its role in the brain.
Results:
We examined the overall distribution of L1 in the adult mouse brain by immunohistochemistry using two polyclonal antibodies against different epitopes for L1. Immunoreactive L1 was widely but unevenly distributed from the olfactory bulb to the upper cervical cord. The accumulation of immunoreactive L1 was greatest in a non-neuronal element of the major fibre bundles, i.e. the lateral olfactory tract, olfactory and temporal limb of the anterior commissure, corpus callosum, stria terminalis, globus pallidus, fornix, mammillothalamic tract, solitary tract, and spinal tract of the trigeminal nerve. High to highest levels of non-neuronal and neuronal L1 were found in the grey matter; i.e. the piriform and entorhinal cortices, hypothalamus, reticular part of the substantia nigra, periaqueductal grey, trigeminal spinal nucleus etc. High to moderate density of neuronal L1 was found in the olfactory bulb, layer V of the cerebral cortex, amygdala, pontine grey, superior colliculi, cerebellar cortex, solitary tract nucleus etc. Only low to lowest levels of neuronal L1 were found in the hippocampus, grey matter in the caudate-putamen, thalamus, cerebellar nuclei etc.
Conclusion:
L1 is widely and unevenly distributed in the matured mouse brain, where immunoreactivity was present not only in neuronal elements; axons, synapses and cell soma, but also in non-neuronal elements.
