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Multiple Interacting Sites of Ectopic Spike Electrogenesis in Primary Sensory Neurons
- Source :
- The Journal of Neuroscience. 25:2576-2585
- Publication Year :
- 2005
- Publisher :
- Society for Neuroscience, 2005.
-
Abstract
- Ectopic discharge generated in injured afferent axons and cell somatain vivocontributes significantly to chronic neuropathic dysesthesia and pain after nerve trauma. Progress has been made toward understanding the processes responsible for this discharge using a preparation consisting of whole excised dorsal root ganglia (DRGs) with the cut nerve attached. In thein vitropreparation, however, spike activity originates in the DRG cell soma but rarely in the axon. We have now overcome this impediment to understanding the overall electrogenic processes in soma and axon, including the resulting discharge patterns, by modifying the bath medium in which recordings are made. At both sites, bursts can be triggered by subthreshold oscillations, a phasic stimulus, or spikes arising elsewhere in the neuron. In the soma, once triggered, bursts are maintained by depolarizing afterpotentials, whereas in the axon, an additional process also plays a role, delayed depolarizing potentials. This alternative process appears to be involved in “clock-like” bursting, a discharge pattern much more common in axons than somata. Ectopic spikes arise alternatively in the soma, the injured axon end (neuroma), and the region of the axonal T-junction. Discharge sequences, and even individual multiplet bursts, may be a mosaic of action potentials that originate at these alternative electrogenic sites within the neuron. Correspondingly, discharge generated at these alternative sites may interact, explaining the sometimes-complex firing patterns observedin vivo.
- Subjects :
- Time Factors
General Neuroscience
Action Potentials
Depolarization
Sensory system
In Vitro Techniques
Biology
Stimulus (physiology)
Article
Rats
Antidromic
Bursting
medicine.anatomical_structure
Electricity
nervous system
Biological Clocks
Ganglia, Spinal
medicine
Animals
Soma
Neurons, Afferent
Neuron
Rats, Wistar
Axon
Neuroscience
Subjects
Details
- ISSN :
- 15292401 and 02706474
- Volume :
- 25
- Database :
- OpenAIRE
- Journal :
- The Journal of Neuroscience
- Accession number :
- edsair.doi.dedup.....897039b634381311c6f09355d986730c