Gangliosides in Axolemmal and Synaptic Membrane Fractions from Developing Rats: Effects of Maternal Ethanol Consumption on Offspring

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Abstract
Previous work from this laboratory has shown that in utero exposure to ethanol significantly alters the synthesis of glycoproteins in synaptic, axolemmal, and myelin membranes from developing rats. In an attempt to determine whether in utero exposure to ethanol similarly alters the synthesis of other glycoconjugates involved with cell‐cell interactions, the present study examined the influence of chronic maternal ethanol consumption prior to parturition on the content and synthesis of gangliosides in axolemmal and synaptic plasma membranes from developing rats. The results demonstrate that, in contrast to central nervous system glycoproteins, synaptic and axolemmal glycoUpids are minimally affected by in utero exposure to ethanol. At all ages examined (17 to 34 days of age), the offspring of control and ethanol‐treated rats had a comparable distribution of radiolabel among synaptic and axolemmal gangliosides, a normal concentration of ganglioside sialic acid in synaptic plasma membranes, and a near‐normal distribution of sialic acid among synaptic gangliosides. The present study provides evidence which indicates that the radiolabeling patterns of axolemmal and synaptic membrane gangliosides are similar. Specifically, the most heavily labeled synaptic and axolemmal gangliosides were G11b (20–37% of the total radioactivity) and G01s (20–32%). A smaller proportion of radioactivity was associated with G01b (∼ 11–16%), GM1 (5–10%), and G01b (4–11%), as well as with GD3 and the other monosialogangliosides (< 5%). During the age period examined the proportion of radioactive Grit increased in both membrane fractions.