Synaptophysin: an immunohistochemical marker for animal dysautonomias

Equine and feline dysautonomias are characterized histopathologically by degenerating neurons with chromatolysis, pyknotic and sometimes eccentric nuclei, and loss of Nissl substance in the peripheral autonomic ganglia. Because it may be difficult to distinguish pathological from post-mortem changes in affected ganglia by histopathological examination, synaptophysin was evaluated as an immunohistochemical marker. Degenerating neurons showed strong intracytoplasmic labelling indicating abnormal accumulation of synaptophysin. It was concluded that synaptophysin immunohistochemistry is a helpful tool for detecting degenerating neurons in equine (grass sickness) and feline (Key-Gaskell syndrome) dysautonomias.