Dopaminergic mesencephalic systems and behavioral performance in very old rats
Abstract
Morphologic and functional studies describing the impact of aging on mesencephalic dopaminergic (DA) neurons in laboratory animals are rather scanty and inconclusive. In rats, stereological studies characterizing age changes in the mesencephalic DA neurons have not been documented. In order to fill this information gap and to determine whether the very old rat may serve as a suitable animal model of Parkinson's disease, we performed a stereological assessment of the mesencephalic tyrosine hydroxylase immunoreactive (TH-ir) neurons in young-adult (4-6 months), old (22-24 months) and senile (30-32 months) Sprague-Dawley female rats. Morphometric analysis of the TH-ir neurons of the substantia nigra (SN) and ventral tegmental area (VTA) was performed using an appropriate image analysis system. Age changes in motor performance were assessed measuring the endurance of rats to hang from a wire mesh pole or to remain on a ramp set at different angles to the floor. Age changes in locomotion and exploratory activity were evaluated by the open field test. We observed a significant age-related reduction in TH-ir neuron numbers in the SN (17 and 33% reduction in old and senile rats, respectively compared with young counterparts) but not in the VTA. The size of the TH-ir cells increased significantly in both the SN and VTA of the senescent animals but TH labeling intensity fell. Motor, locomotor and exploratory performance deteriorated markedly in the old and senile rats as compared with young animals. These findings reveal the existence of a moderate but significant vulnerability of mesencephalic DA neurons to aging in rats. This phenomenon, which is particularly marked in the SN of very old rats, may contribute to the age-related decline in motor and exploratory performance recorded in this species.
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Consistent findings of dopaminergic degeneration have been reported in aged rats.
“Consistent findings have also been recently reported in aged rats [82].”
From A neoHebbian framework for episodic memory; role of dopamine-dependent late LTP (2011) · cites this paper as [82]
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- Authors
- Sanchez, H. L., Silva, L. B., Portiansky, E. L., Herenu, C. B., Goya, R. G., & Zuccolilli, G. O.
- Affiliations
- Universidad Nacional de La Plata (AR)
- Biochemistry Research Institute of La Plata (AR)
- Venue
- Neuroscience
- Publisher
- Elsevier BV
- Published
- 2008-07
- Volume
- 154
- Issue
- 4
- Pages
- 1598-1606
- ISSN
- 0306-4522 (ISSN-L)
- OpenAlex
- W2054101130
- Cited by
- 48
- References
- 38
- Citations by year
- 2026: 2 · 2025: 1 · 2023: 3 · 2022: 3 · 2021: 2 · 2020: 4 · 2018: 2 · 2017: 2 · 2016: 2 · 2015: 1 · 2014: 3 · 2013: 3 · 2012: 2
- FWCI
- 3.78
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Neuroscience (publishedVersion)
- PubMed (publishedVersion)
- Funders
- Fogarty International Center (R21TW006665)
- Topics
- Health Sciences › Medicine › Neurology › Parkinson's Disease Mechanisms and Treatments
- Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neurotransmitter Receptor Influence on Behavior
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Aging › Genetics, Aging, and Longevity in Model Organisms
- Keywords
- midbrain dopaminergic neurons, aging, Parkinson's disease model, substantia nigra, ventral tegmental area, neuron size, motor performance, locomotion, exploratory activity, age-related decline
- MeSH terms
- Aging, Animals, Behavior, Animal, Dopamine, Female, Immunohistochemistry, Mesencephalon, Motor Activity, Neurons, Tyrosine 3-Monooxygenase, Rats, Sprague-Dawley, Rats
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