Vulnerability of the dorsal root ganglion in experimental allergic encephalomyelitis

The dorsal (posterior) root ganglion is a relatively neglected part of the nervous system from the clinical point of view. In recent studies on the pathophysiology of experimental allergic encephalomyelitis (EAE), the main animal model of multiple sclerosis, the DRG of the rabbit was shown to be the site of extensive inflammation and demyelination and of focal conduction block in a high proportion of the large diameter afferents. The resulting severe functional peripheral deafferentation accounts for the postural disturbance, hypotonia, ataxia and areflexia in rabbits with EAE. The vulnerability of the DRG is due to a deficient blood-nerve barrier and possibly also to a susceptibility of the branch point of the ganglion neurone to demyelination-induced conduction block. These and other studies in experimental animals suggest that in man the DRG may be a preferential (but neglected) site of focal structural and functional abnormalities in inflammatory and also other neurological diseases.