Preservation of early discharge of muscle afferents in acrylamide neuropathy.

1. Responses to stretch and the 'early discharge' have been studied in acrylamide neuropathy in the expectation that functional block of the nerve terminals would allow these two processes to be dissociated. 2. Of 538 single group I and group II muscle afferents which were nonresponsive to stretch, ninety-nine displayed 'early discharge' which appeared to be identical with that described in normally functioning muscle stretch afferents. 3. Preservation of 'early discharge' in non-responsive fibres indicates these impulses do not arise from excitation of the muscle spindle itself. The evidence indicates that 'early discharge' is usually ephaptically excited by the muscle action potential.