The biological activity of synthetic ceramide analogues, having modified sphingoid and N- acyl chains, as well as fluorine substituents in the allylic position, was investigated in hippocampal neurons. Their influence on axonal growth was compared to that of C6-N-acyl analogues of natural ceramides. d-erythro-Ceramides with a phenyl group in the sphingoid moiety and a short N-acyl chain were able to reverse the inhibitory effect of fumonisin B1 ( ...