The effect of globopentaosylceramide on a depression model, mouse forced swimming.

We investigated the late effects of serotonergic drugs on mouse forced swimming and found that serotonin 1A antagonist NAN-190 hydrobromide (NAN-190) and serotonin 2 agonist R(-)-DO1 hydrochloride (DO1) increase the typical anti-depressive behavior climbing 6 hours after the intraperitoneal injection. With the use of ion exchanger, ultra filtration and chemical extraction methods, a substance having remarkable anti-depressive activity on mouse forced swimming was extracted from the serums of the mice treated with the drugs. The substance was strongly suggested to be a glycolipid having a specific sugar chain structure GalNAcalpha1-3GalNAc in its terminal. In fact, globopentaosylceramide, another glycolipid having the structure in the terminal also showed marked anti-depressive activity on mouse forced swimming, but globotetraosylceramide lacking the sugar chain structure did not. The GalNAcalpha1-3GalNAc-lipid reactivity in the serum and typical anti-depressive behavior climbing increased corresponding to the doses of NAN-190 and DO1. These findings clearly indicate that the terminal structure GalNAcalpha1-3GalNAc has the essential role in the anti-depressive activity of globopentaosylceramide, and that serotonin 1A antagonism and serotonin 2 agonism increase the production of an anti-depressive glycolipid having the terminal structure in mouse serum.

Immunogenic properties of mannose-containing ceramide tetrasaccharide from fresh-water bivalve, Hyriopsis schlegelii.

Antiserum against GlcNAc beta 1----2Man alpha 1----3Man beta 1----4Glc beta 1----1Cer (MlOse4Cer), a mannolipid isolated from spermatozoa of the fresh-water bivalve Hyriopsis schlegelii, was elicited in rabbits by repeated injection of a mixture of hapten-bovine serum albumin with Freund's adjuvant. The specificity of the affinity-purified antibody obtained from the serum was based on two forms of enzyme-immunodetection of its binding to structurally related glycolipids, either adsorbed to microtiter plates or chromatographed on thin-layer plates. The purified antibody exhibited a significant cross-reactivity with GlcNAc beta 1----2Man alpha 1----3(Xyl beta 1----2)Man beta 1----4Glc beta 1----1Cer, (MIXOse5Cer) containing a core structure closely related to MlOse4Cer, but almost unrelated to other glycolipids. Distribution of MlOse4Cer and MlXOse5Cer in various bivalve and snail glycolipid extracts were screened in thin-layer immunobinding assays by using this purified specific antibody. The presence of the glycolipid antigens was limited to certain taxonomic orders of shellfish species.