Acute conduction block associated with experimental antiserum-mediated demyelination of peripheral nerve

Intraneural injection of antisera from rabbits with high antigalactocerebroside antibody levels into rat sciatic nerve produced acute nerve conduction block. This was first apparent in some motor axons between 30 and 60 minutes after injection and progressed to completion within 2 to 4 hours. Concurrent morphological evidence of demyelination was present, but structural changes at the time of onset of block were mild and were restricted to the myelin and Schwann cell, particularly at the paranodal areas and Schmidt-Lanterman clefts. It is suggested that paranodal lesions could account for the observed conduction block.