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Comparison between electrophysiologic and morphologic changes in lead induced peripheral neuropathy in rats
Y M Hwang1, I N Sunwoo, I H Chung
1Department of Neurology, Asan Medical Center, Ulsan University College of Medicine, Korea.
Journal of Korean Medical Science
|December 1, 1989
Summary
Lead poisoning significantly impairs peripheral nerve function in rats, particularly affecting large myelinated nerve fibers. Electrophysiologic changes observed in lead-poisoned rats correlate with nerve pathology, indicating nerve damage.
Area of Science:
- Neuroscience
- Toxicology
- Peripheral Nerve Physiology
Background:
- Compound nerve action potentials (CNAPs) reflect the electrical activity of different nerve fiber types.
- Lead exposure is a known neurotoxin, but its specific effects on peripheral nerve fiber subtypes require detailed investigation.
Purpose of the Study:
- To investigate the electrophysiologic and pathologic effects of lead poisoning on rat peripheral nerves.
- To correlate changes in nerve conduction velocity and amplitude with nerve fiber morphology.
Main Methods:
- Recording of compound nerve action potentials (CNAPs) from the sciatic nerve in control and lead-poisoned rats.
- Stimulation of the tibial nerve to elicit A alpha beta, A delta, and C fiber potentials.
- Histopathological examination of nerve tissue to assess myelination and axonal integrity.
Main Results:
- Lead poisoning caused a marked decrease in nerve conduction velocity and prolonged duration in A alpha beta and A delta fibers, especially large myelinated ones.
- A alpha beta potentials showed decreased amplitude without changes in area, while C potentials (unmyelinated fibers) had minimal changes.
- Pathology revealed significant segmental demyelination and reduced large myelinated fiber density, with minimal axonal degeneration in unmyelinated fibers.
Conclusions:
- Electrophysiologic alterations in lead-poisoned rats are consistent with observed nerve pathology.
- Lead exposure primarily targets large myelinated peripheral nerve fibers, causing demyelination and functional deficits.