Neuritogenic and chemical properties of guinea pig anterior and posterior root myelin.

In relapsing experimental allergic encephalomyelitis, recurrent demyelination was found in the anterior roots and dorsal root ganglia with minimal involvement of the posterior roots. To determine whether this is an antigen-related phenomenon, the distribution, type and intensity of the lesions in the proximal PNS of guinea pigs immunized with anterior roots or myelin were compared to those of animals immunized with posterior roots or myelin. Homologous anterior roots were less neuritogenic than posterior roots or posterior root myelin. Thin layer chromatography of myelin samples from anterior and posterior roots, dorsal root ganglia and sciatic nerve revealed the presence of a sulfogalactoglycerolipid, tentatively identified as sulfated galactosylglyceride (SGG) in all but the posterior root myelin samples. Although the PNS lesions of relapsing experimental allergic encephalomyelitis appear to recapitulate the regional distribution of SGG, the reason why its presence in anterior roots myelin renders them less neuritogenic is at present not clear.