Expression of neolactoglycolipids: sialosyl-, disialosyl-,O-acetyldisialosyl- and fucosyl- derivatives of neolactotetraosyl ceramide and neolactohexaosyl ceramide in the developing cerebral cortex and cerebellum

The following neolacto glycolipids were identified and their developmental expression was studied in the rat cerebral cortex and cerebellum: Fuc1-³IIInLcOse₄Cer,Fuc1-³VnLcOse₆Cer and (Fuc)₂1-³III,³VnLcOse₆Cer, as well as acidic glycolipids, NeuAc2-³IVnLcOse₄Cer [nLM1], (NeuAc)₂2-³IVnLcOse₄Cer [nLD1],O-acetyl (NeuAc)₂2-³IVnLcOse₄Cer [OAc-nLD1] and their higher neolactosaminyl homologues NeuAc2-³VInLcOse₆Cer [nHM1] and (NeuAc)₂2-³VInLcOse₆Cer [nHD1]. These glycolipids were expressed in the cerebral cortex only during embryonic stages and disappeared postnatally. This loss was ascribed to the down regulation of the synthesis of the key precursor LcOse₃Cer which is synthesized by the enzyme lactosylceramide:N-acetylglucosaminyl transferase. On the other hand in the cerebellum, these glycolipids increased with postnatal development due to increasing availability of LcOse₃Cer. In the cerebellum, only nLM1 and fucosyl-neolactoglycolipids declined after postnatal day 10–15, perhaps due to regulation by other glycosyltransferases. Also, in the cerebellum, nLD1 and nHD1 were shown to be specifically associated with Purkinje cells and their dendrites in the molecular layer and with their axon terminals in the deep cerebellar nuclei, similar to other neolactoglycolipids shown previously.