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Systemic lidocaine silences ectopic neuroma and DRG discharge without blocking nerve conduction
Marshall Devor1, Patrick D Wall, Naor Catalan
1Neurobehavior Unit, Department of Zoology, Life Sciences Institute, Hebrew University of Jerusalem, Jerusalem 91904 Israel Cerebral Functions Group, Department of Anatomy and Developmental Biology, University College London, London WC1E 6BT U.K.
Pain
|February 1, 1992
Summary
Systemic lidocaine effectively suppressed abnormal nerve impulses in rats, particularly in dorsal root ganglion cells, offering potential for neuropathic pain relief.
Area of Science:
- Neuroscience
- Pharmacology
Background:
- Neuropathic pain involves abnormal nerve impulse generation.
- Local anesthetics like lidocaine are used to manage pain.
Purpose of the Study:
- To investigate the effect of systemic lidocaine on ectopic impulse discharge in experimental nerve injury models.
- To determine the selectivity of lidocaine's action on injured versus normal nerve fibers.
Main Methods:
- Systemic administration of lidocaine to rats with experimental nerve injury.
- Assessment of ectopic impulse discharge in dorsal root ganglion (DRG) cells and nerve injury sites.
- Evaluation of lidocaine's effect on impulse initiation and propagation via electrical stimulation.
- Testing effects on normal sensory receptors.
Main Results:
- Lidocaine suppressed ectopic discharges in both injured nerves and axotomized DRG cells.
- The effective dose (ED50) for DRG cells was lower than for the injury site.
- Lidocaine did not block impulse initiation/propagation from electrical stimulation and minimally affected normal receptors.
Conclusions:
- Lidocaine's selective suppression of ectopic discharges contributes to its efficacy in neuropathic pain.
- This mechanism explains the effectiveness of systemic local anesthetics, anticonvulsants, and antiarrhythmics for neuropathic pain.
- Selectivity may also explain prolonged analgesia from regional nerve blocks.