FUCOSYLATION of terminal galactose residues of brain glycoproteins in th eα(1–2) position has been shown to be crucial for neuronal plasticity, including phenomena such as long-term potentiation and long-term memory formation. We raised antibodies against the plasticity- relevant fu α(1-2)gal epitope and used them to determine the distribution of the epitope in adult rat hippocampus. To identify proteins bearing fu α(d-2)gal glycostructures antibodies against known synaptic fucoglycoproteins were used in combination with the fucα(1-2)gal antibodies. The NMDA receptor subunit NR1 and fractions of gp65 and cadherin were found to carry the epitope, while fucosylation of NCAM180 and NCAM140 obviously occurs via different linkages to the glycan chains.