Myelin Gangliosides: An Unusual Pattern in the Avian Central Nervous System

Abstract: Gangliosides were isolated from purified myelin obtained from brain and spinal cord of mature chickens and pigeons. Total concentrations were approximately two‐ to fivefold greater than for previously reported mammalian species, and their patterns also differed in containing significantly more sialosylgalactosylceramide (G_M4). The latter comprised one‐third to one‐fourth of total myelin ganglioside, approximately equivalent to G_M1 (II³NeuNAc‐GgOse₄Cer). As in mammals, G_M4 of avian CNS appeared to be localized in myelin. Fatty acids of this ganglioside included both the hydroxy‐ and unsubstituted types. and, long‐chain bases were almost entirely C₁₈. Ganglioside G_M1 split into two closely migrating bands on TLC, the slower of which resembled mammalian G_M1 in having stearate as the main fatty acid with a measurable amount (10%) of C₂₀‐sphingosine; the faster band had predominantly longer‐chain fatty acids and very little C₂₀‐sphingosine.