Loss and remodeling of striatal dendritic spines in Parkinson's disease: from homeostasis to maladaptive plasticity?
Level 5 - mechanism / opinion, no new human data
Narrative review of preclinical and clinical mechanistic literature without systematic methodology.
PubMed 28540422 · doi:10.1007/s00702-017-1735-6
What was done
The authors reviewed 30 years of literature from Parkinson's disease patients and animal models examining structural alterations in striatal projection neurons following nigrostriatal dopamine degeneration, specifically evaluating dendritic spine loss, axospinous glutamatergic synaptic remodeling, and model limitations.
What was found
The abstract reports no quantitative metrics or effect sizes. Qualitatively, striatal spine loss occurs early and correlates tightly with the extent of dopamine denervation rather than motor symptom severity, potentially reflecting homeostatic compensation. Conversely, late-stage remodeling of corticostriatal and thalamostriatal glutamatergic synapses is associated with altered synaptic strength, heightened bursting activity of striatal projection neurons, and L-DOPA-induced dyskinesia.
Why it matters
It contextualizes structural striatal changes as a two-phase process transitioning from initial adaptive compensation to maladaptive synaptic rewiring relevant to Parkinson's disease progression and treatment complications.
Limits
The abstract provides no quantitative data, search methodology, or study inclusion criteria. Major controversies highlighted include unresolved differences across striatal projection neuron subtypes, unclear causal links between spine remodeling and altered neuronal firing, and uncertain translational validity of animal models to human disease.
Cited by
- supports Dopamine is required for synapse formation and synaptic plasticity, and dopamine depletion drives the loss of neural connections in Parkinson's disease.