Nodes of Ranvier are regular gaps in the myelin sheath where action potentials are regenerated via voltage-gated sodium channels. These specialized axonal regions are particularly vulnerable in neurodegenerative diseases.
- Node lengthening in motor neurons
- Sodium channel dispersion
- Conduction deficits
- Early pathological marker
- Paranodal degradation
- Node dysfunction
- Autonomic failure link
- Oligodendrocyte involvement
- Primary demyelination
- Node remodeling
- Sodium channel redistribution
- Progressive neuropathy
| Component |
Function |
Disease Changes |
| Nav1.6 |
Depolarization |
Altered |
| Ankyrin-G |
Scaffold |
Disrupted |
| Caspr2 |
Organization |
Reduced |
| Contactin |
Myelin contact |
Lost |
- Sodium channel modulators: Maintain function
- Myelin stabilizers: Protect oligodendrocytes
- Ankyrin-G enhancers: Scaffold protection
- Neurotrophic factors: Axonal support
MSA involves prominent node pathology:
- Degeneration of paranodal loops
- Disruption of axo-glial junctions
- Sodium channel dispersion
- Conduction failure
- α-synuclein inclusion formation
- Myelin basic protein loss
- White matter degeneration
- Autonomic nuclei targeting
- Orthostatic hypotension
- Cerebellar ataxia
- Parkinsonism
- Autonomic failure
CMT represents inherited peripheral neuropathy:
- PMP22 duplication
- Myelin protein loss
- Onion bulb formation
- Node remodeling
- Primary axonal degeneration
- Secondary myelin changes
- Distal weakness
- Sensory loss
- Nav channel redistribution
- Paranodal abnormalities
- Conduction slowing
- Temporal dispersion
Node integrity depends on axonal transport:
| Transport Protein |
Function |
Disease Change |
| Kinesin |
Anterograde |
Impaired |
| Dynein |
Retrograde |
Dysfunctional |
| JIP3 |
Kinesin adaptor |
Reduced |
| BICD2 |
Dynactin complex |
Mutated in disease |
- Ankyrin-G degradation
- Spectrin network breakdown
- Actin polymerization defects
- Microtubule instability
- Nav channel trafficking: Impaired delivery
- Channel degradation: Accelerated loss
- Splice variants: Alternative isoforms
- Phosphorylation changes: Altered gating
| Target |
Agent |
Status |
| Sodium channels |
Riluzole |
Approved |
| Neurotrophins |
BDNF |
Research |
| Cytoskeleton |
Cytoskeletal stabilizers |
Preclinical |
| Transport |
Axonal transport enhancers |
Research |
- Oligodendrocyte precursors: Activation
- Myelin repair agents: Promote regeneration
- Cell transplantation: Stem cell therapy
- Gene therapy: Target genetic forms
- Nerve conduction studies
- F-wave analysis
- Motor unit estimates
- Quantitative sensory testing
- MRI nerve root imaging
- Diffusion tensor imaging
- MR neurography
- PET myelin imaging
- CMT1A mice (PMP22 duplication)
- Dysmyelinated mutants
- Transgenic models
- Knockout systems
- Neuronal cultures
- Myelin co-cultures
- Organotypic slices
- iPSC-derived neurons
- PMP22 silencing
- MPZ replacement
- GJB1 delivery
- Custom approaches
- Channel modulators
- Cytoskeletal stabilizers
- Neurotrophic compounds
- Anti-inflammatory agents