We have examined the ultrastructure of the striatum in squirrel monkeys 1-5 d after a single sc injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) 2.5 mg/kg. One untreated monkey served as control. We expected to find a dense degeneration of the dopamine terminals, but found instead that the main abnormality consisted of a focal vacuolation of the tissue, perhaps related to the striosome/matrix mosaic of the neostriatum. The vacuolation involved not only terminals, but also other parts of the neuropil. The severity of the destructive process increased from d 1-5. We conclude that MPP+, the toxic metabolite of MPTP, may gain access to the neuropil, either before or after its active uptake into and subsequent destruction of the dopamine terminals. In the present study, abnormalities were observed simultaneously in the striatum and substantia nigra as early as 24 h after MPTP administration. It is, however, possible that the time-course might differ between the two locations with even shorter time intervals or changes in dosage of MPTP.
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http://dx.doi.org/10.1007/BF02816116 | DOI Listing |
Front Neural Circuits
January 2025
Department of Advanced Medical and Surgical Sciences, Advanced MRI Research Center, University of Campania "Luigi Vanvitelli", Naples, Italy.
The substantia nigra pars compacta (SNc), one of the main dopaminergic nuclei of the brain, exerts a regulatory function on the basal ganglia circuitry via the nigro-striatal pathway but its possible dopaminergic innervation of the thalamus has been only investigated in non-human primates. The impossibility of tract-tracing studies in humans has boosted advanced MRI techniques and multi-shell high-angular resolution diffusion MRI (MS-HARDI) has promised to shed more light on the structural connectivity of subcortical structures. Here, we estimated the possible dopaminergic innervation of the human thalamus via an MS-HARDI tractography of the SNc in healthy human young adults.
View Article and Find Full Text PDFNeuropharmacology
January 2025
Department of Anatomy & Neuroscience, School of Medicine, University College Cork (UCC), Cork, Ireland; APC Microbiome Ireland, UCC, Cork, Ireland. Electronic address:
Degeneration of midbrain nigrostriatal dopaminergic neurons is a pathological hallmark of Parkinson's disease (PD). Peripheral delivery of a compound(s) to arrest or slow this dopaminergic degeneration is a key therapeutic goal. Pan-inhibitors of histone deacetylase (HDAC) enzymes, key epigenetic regulators, have shown therapeutic promise in PD models.
View Article and Find Full Text PDFZhejiang Da Xue Xue Bao Yi Xue Ban
January 2025
School of Medicine, Hangzhou City University, Zhejiang Provincial Key Laboratory of Novel Targets and Drug Study for Neural Repair, Hangzhou 310015, China.
Objectives: To investigate the protective effects and underlying mechanisms of extract on motor dysfunction in mouse model of Parkinson's disease (PD).
Methods: Eighty C57BL/6 male mice were randomly divided into five groups: control group, PD model group, levodopa treatment group (positive control group), low-dose GP treatment group (LD-GP group), and high-dose GP treatment group (HD-GP group), with 16 mice per group. The PD model was induced by injection of 6-hydroxydopamine into the substantia nigra pars reticulata in mice of last 5 groups.
Brain Behav Immun
January 2025
Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA; Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA. Electronic address:
Inflammatory stimuli administered to humans and laboratory animals affect mesolimbic and nigrostriatal dopaminergic pathways in association with impaired motivation and motor activity. Alterations in dopaminergic corticostriatal reward and motor circuits have also been observed in depressed patients with increased peripheral inflammatory markers. The effects of peripheral inflammation on dopaminergic pathways and associated neurobiologic mechanisms and consequences have been difficult to measure in patients.
View Article and Find Full Text PDFJ Neurosci
January 2025
Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, 9 Gronostajowa street, 30-387 Kraków, Poland.
Dopaminergic (DA) neurons of the substantia nigra pars compacta (SNc) and ventral tegmental area (VTA) play a crucial role in controlling animals' orienting and approach behaviors toward relevant environmental stimuli. The ventral midbrain receives sensory input from the superior colliculus (SC), a tectal region processing information from contralateral receptive fields of various modalities. Given the significant influence of dopamine release imbalance in the left and right striatum on animals' movement direction, our study aimed to investigate the lateralization of the connection between the lateral SC and the midbrain DA system in male rats.
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