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Preparation of Acute Hippocampal Slices from Rats and Transgenic Mice for the Study of Synaptic Alterations during Aging and Amyloid Pathology
Published on: March 23, 2011
Region-specific decline in the expression of metabotropic glutamate receptor 7 mRNA in rat brain during aging
A Simonyi1, L A Miller, G Y Sun
1Department of Biochemistry, University of Missouri, Columbia, MO 65212, USA. simonyia@health.missouri.edu
Abstract:
Age-dependent changes in the expression of group III metabotropic glutamate receptors (mGluR4 and mGluR7) were studied by quantitative in situ hybridization using male Fisher 344 rats 3, 12 and 25 months of age. Results indicate an early decrease in mGluR7 mRNA level in several cortical areas including the frontal, parietal and temporal cortices. In the hippocampus, mGluR7 mRNA levels decreased in the CA1 region and the lower blade of the dentate gyrus. Moreover, significant decrease was found in the laterodorsal thalamic nucleus at 12 months of age. Other regions such as the caudate putamen and nucleus accumbens showed no age-related changes in mGluR7 mRNA levels. Analysis of emulsion autoradiograms revealed a 36% decrease of mGluR7 mRNA in Purkinje neurons in the 12-month-old group and a 48% decline in the 25-month-old group as compared to the 3-month-old group. A substantial decrease in mGluR4 mRNA level was found in the granule cell layer of the cerebellum during aging. The difference between the young and aged groups exceeded 35%. These region-specific decreases may have important implication in some of the age-related changes in cognitive, motor and/or sensory functions.
Insights
Group III metabotropic glutamate receptors (mGluR4 and mGluR7) expression declines with age in specific brain regions. This age-related decrease in mGluR4 and mGluR7 mRNA may impact cognitive, motor, and sensory functions.
Area of Science:
- Neuroscience
- Aging Research
- Molecular Biology
Background:
- Group III metabotropic glutamate receptors (mGluR4 and mGluR7) play crucial roles in neuronal function.
- Age-related alterations in neurotransmitter systems are linked to functional declines.
Purpose of the Study:
- To investigate age-dependent changes in the expression of mGluR4 and mGluR7.
- To identify brain regions affected by aging in relation to these receptors.
Main Methods:
- Quantitative in situ hybridization was employed.
- Male Fisher 344 rats of three age groups (3, 12, and 25 months) were analyzed.
Main Results:
- mGluR7 mRNA levels decreased in cortical areas (frontal, parietal, temporal) and hippocampus (CA1, dentate gyrus).
- Significant reductions in mGluR7 mRNA were observed in the laterodorsal thalamic nucleus and Purkinje neurons with age.
- mGluR4 mRNA levels substantially decreased in the cerebellar granule cell layer.
Conclusions:
- Aging leads to region-specific decreases in mGluR4 and mGluR7 mRNA expression.
- These molecular changes may underlie age-related deficits in cognitive, motor, and sensory functions.
