Memantine protects cholinergic and glutamatergic septal neurons from Aβ1-40-induced toxicity
L V Colom1, M T Castaneda, D Aleman
1Center for Biomedical Research, The University of Texas at Brownsville, 80 Fort Brown, Brownsville, TX 78520, USA. Luis.colom@utb.edu
Abstract:
The medial septal region (medial septum and diagonal band of Broca, MS/DB) controls hippocampal excitability and synaptic plasticity. MS/DB cholinergic neurons degenerate early in Alzheimer's disease (AD). The presence of MS/DB glutamatergic neurons that project to the hippocampus and are vulnerable to Aβ suggests that excitotoxicity plays a role in AD septal degeneration and hippocampal dysfunction. To demonstrate the presence of excitotoxicity in Aβ-induced septal damage, we compared rats injected with Aβ1-40 into the MS/DB with animals treated with memantine prior, during and after Aβ1-40 injections. Controls were injected with phosphate buffered saline (PBS). MS/DB cholinergic, glutamatergic and GABAergic neurons were immunochemically identified. The number of MS/DB neurons was estimated using stereology. Our results show that memantine blocks Aβ1-40-induced septal damage and suggest that excitotoxicity plays a role in basal forebrain neurodegeneration.
Insights
Alzheimer's disease (AD) involves medial septal region (MS/DB) degeneration. This study shows memantine prevents amyloid-beta (Aβ)-induced damage, suggesting excitotoxicity contributes to neurodegeneration in AD.
Area of Science:
- Neuroscience
- Neurodegenerative Diseases
- Alzheimer's Disease Research
Background:
- The medial septal region (MS/DB) regulates hippocampal function.
- Cholinergic neurons in the MS/DB degenerate early in Alzheimer's disease (AD).
- Vulnerability of MS/DB glutamatergic neurons to amyloid-beta (Aβ) suggests excitotoxicity in AD.
Purpose of the Study:
- To investigate the role of excitotoxicity in Aβ-induced damage to the MS/DB.
- To evaluate the neuroprotective effects of memantine against Aβ toxicity in the basal forebrain.
Main Methods:
- Rats received Aβ1-40 injections into the MS/DB.
- Memantine treatment was administered before, during, and after Aβ1-40 injections.
- Immunohistochemistry and stereology were used to quantify neuronal populations (cholinergic, glutamatergic, GABAergic) in the MS/DB.
Main Results:
- Aβ1-40 injection into the MS/DB caused significant septal damage.
- Memantine treatment effectively blocked Aβ1-40-induced neurodegeneration in the MS/DB.
- Specific neuronal subtypes within the MS/DB were affected by Aβ1-40.
Conclusions:
- Excitotoxicity plays a significant role in Aβ-induced septal degeneration.
- Memantine demonstrates neuroprotective potential against Aβ-mediated basal forebrain neurodegeneration.
- These findings support the involvement of excitotoxicity in the pathogenesis of Alzheimer's disease.
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