Effects of 4-aminopyridine in experimental CNS demyelination

We studied the effect of systemically administered 4-aminopyridine in a model of CNS demyelination. In five rats with demyelination, slowed conduction velocity through the lesion was partially reversed at dose levels of 5.6 to 7.2 mg/kg. All rats developed convulsion at this dosage, and impaired conduction of high-frequency impulses was unchanged. These findings suggest certain limitations of 4-aminopyridine as a therapeutic agent.