Impairment of repetitive impulse conduction in experimentally demyelinated and pressure-injured nerves.
Repetitive impulse conduction was studied in segmentally demyelinated peripheral nerves in guinea-pigs with experimental allergic neuritis (EAN) and in pressure-injured frog sciatic nerves. Normal guinea-pig sciatic-peroneal nerves maintained at 37°C conducted compound action potentials with only minor amplitude decreases at stimulus frequencies up to 200/sec. In contrast, nerves in EAN guinea-pigs maintained at 37°C demonstrated a rapidly progressive decrease in action potential amplitude when stimulated as slowly as 10-25/sec. The decrease is greater the higher the frequency of stimulation. At 100 stimuli/sec all EAN preparations showed more than a 50% reduction in action potential amplitude. These effects are reversible. In pressure-injured frog sciatic nerves similar effects occurred at stimulus frequencies as low as 50/sec. Normal frog nerves conducted up to 200 impulses/sec with little amplitude decrease. The probable mechanism and clinical significance of these results are discussed.
D000200:Action Potentials; D000818:Animals; D001001:Anura; D003711:Demyelinating Diseases / Q000503:physiopathology*; D006168:Guinea Pigs; D009408:Nerve Compression Syndromes / Q000503:physiopathology; D009431:Neural Conduction; D010525:Peripheral Nerves / Q000503:physiopathology*; D010523:Peripheral Nervous System Diseases / Q000503:physiopathology*; D011894:Rana pipiens; D012584:Sciatic Nerve / Q000503:physiopathology