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TNF-alpha differentially modulates ion channels of nociceptive neurons.
- Source :
-
Neuroscience letters [Neurosci Lett] 2008 Apr 04; Vol. 434 (3), pp. 293-8. Date of Electronic Publication: 2008 Feb 06. - Publication Year :
- 2008
-
Abstract
- Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine involved in the development and maintenance of inflammatory and neuropathic pain conditions. The mechanisms by which TNF-alpha elicits pain behavior are still incompletely understood. Numerous studies suggest that TNF-alpha sensitizes primary afferent neurons. Most recently, it was shown that TNF-alpha induced an enhancement of TTX-R Na(+) current in dorsal root ganglion (DRG) cells. In the present study, we have tested the effect of acute application of TNF-alpha on voltage-gated potassium, calcium and sodium channel currents as well as its influence on membrane conductance in isolated rat DRG neurons. We report that voltage-gated potassium channel currents of nociceptive DRG neurons are not influenced by TNF-alpha (100 ng/ml), while voltage-gated calcium channel currents were decreased voltage-dependently by -7.73+/-6.01% (S.D.), and voltage-activated sodium channels currents were increased by +5.62+/-4.27%, by TNF-alpha. In addition, TNF-alpha induced a significant increase in IV ramps at a potential of +20 mV, which did not exist when the experiments were conducted in a potassium-free solution, indicating that this effect is mainly the result of a change in potassium conductance. These different actions of TNF-alpha might help to explain how it sensitizes primary afferent neurons after nerve injury and thus facilitates pain.
- Subjects :
- Animals
Calcium Channels drug effects
Calcium Channels metabolism
Cells, Cultured
Ganglia, Spinal drug effects
Hyperalgesia metabolism
Hyperalgesia physiopathology
Ion Channel Gating drug effects
Ion Channels drug effects
Male
Membrane Potentials drug effects
Membrane Potentials physiology
Neuralgia metabolism
Neuralgia physiopathology
Neurons, Afferent drug effects
Nociceptors drug effects
Potassium Channels drug effects
Potassium Channels metabolism
Rats
Rats, Wistar
Sodium Channels drug effects
Sodium Channels metabolism
Time Factors
Tumor Necrosis Factor-alpha pharmacology
Ganglia, Spinal metabolism
Ion Channel Gating physiology
Ion Channels metabolism
Neurons, Afferent metabolism
Nociceptors metabolism
Tumor Necrosis Factor-alpha metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0304-3940
- Volume :
- 434
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Neuroscience letters
- Publication Type :
- Academic Journal
- Accession number :
- 18314270
- Full Text :
- https://doi.org/10.1016/j.neulet.2008.01.070