Autonomic nerves in experimental allergic neuritis in the rat.

After experimental allergic neuritis (EAN) was induced in 16 male Lewis rats with bovine peripheral myelin and adjuvants, peripheral nerves were examined morphologically at intervals of 12-21 days post inoculation (dpi). Signs of motor involvement were present in ten rats and were first elicited 12 dpi. They ranged from tail droop to complete lower limb paralysis. Autonomic nervous system (ANS) involvement was studied by contrasting morphological findings in the cervical sympathetic nerves (CSN), which are poorly myelinated and vagal nerves (VN) which contain numerous myelinated fibers in the endoneurium. Edema, perivenular infiltrates, and demyelination appeared in the VN of seven of nine neurologically affected rats, while the CSN showed edema and infiltrates in only one rat. ELISA assays were negative for anti-galactocerebroside antibody, and electron microscopy failed to show abnormalities of Schwann cells.