Back to Search
Start Over
L-Dopa treatment abolishes the numerical increase in striatal dopaminergic neurons in parkinsonian monkeys
- Source :
- Journal of chemical neuroanatomy. 35(1)
- Publication Year :
- 2007
-
Abstract
- The striatum harbors a population of dopaminergic interneurons that increases in number in animal models of Parkinson's disease (PD), presumably to compensate for dopamine (DA) depletion. The purpose of the present study was to determine the fate of striatal dopaminergic neurons in parkinsonian monkeys in which striatal DA depletion had been alleviated by systemic administration of l-dopa. The number of striatal dopaminergic neurons, visualized with tyrosine hydroxylase (TH) immunohistochemistry, was measured in three groups of cynomolgus (Macaca fascicularis) monkeys: (1) normal untreated monkeys; (2) monkeys rendered parkinsonian following systemic injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), but otherwise untreated; and (3) MPTP-intoxicated monkeys that received oral l-dopa on a chronic basis. In agreement with previous studies, the number of striatal TH-positive (TH+) neurons in l-dopa-free parkinsonian monkeys was significantly higher (p0.05) than in normal (non-parkinsonian) monkeys. However, this increase was abolished in parkinsonian monkeys that received l-dopa treatment. In fact, the number of striatal TH+ neurons in l-dopa-treated parkinsonian monkeys was not significantly different (p0.05) from values obtained in normal monkeys. These findings suggest that the DA concentration regulates the numerical density of this ectopic neuronal population, a phenomenon that is more likely the result of a shift in the phenotype of preexistent striatal interneurons rather than the recruitment of newborn neurons that would eventually develop a DA phenotype. Our data also reinforce the hypothesis that striatal TH+ neurons act as local DA source and, as such, are part of a compensatory mechanism that could be artificially enhanced to alleviate or delay PD symptoms.
- Subjects :
- Parkinson's disease
Tyrosine 3-Monooxygenase
Dopamine
Population
Cell Count
Striatum
Biology
Antiparkinson Agents
Levodopa
Cellular and Molecular Neuroscience
chemistry.chemical_compound
Parkinsonian Disorders
Interneurons
Basal ganglia
medicine
Animals
education
education.field_of_study
Tyrosine hydroxylase
MPTP
Dopaminergic
medicine.disease
Adaptation, Physiological
Immunohistochemistry
Corpus Striatum
Up-Regulation
Disease Models, Animal
Macaca fascicularis
Phenotype
nervous system
chemistry
Female
Neuroscience
medicine.drug
Subjects
Details
- ISSN :
- 08910618
- Volume :
- 35
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Journal of chemical neuroanatomy
- Accession number :
- edsair.doi.dedup.....040c7ceac96e55e6772a481476dd3798