Method for the OsO4-free preservation of brain tissue suitable for immunocytochemistry in TEM

Following conventional OsO4-fixation and embedding of brain tissue in Epoxide resins for ultrastructural investigations, on the one hand, the wellknown good depiction of structures is obtained, on the other hand, however, according to these procedures a considerable loss up to 80% of glycolipid-bound and up to 50% of glycoprotein-bound neuraminic acid of important native compounds has to be put up with. The fixation of brain tissue by 1% glutaraldehyde and 1% paraformaldehyde in 0.1 mol/l Na-K-phosphate-buffer, followed by dehydration in acetone or ethanol at--25 degrees C and embedding in Lowicryl K4M preserves for instance amphiphilic glycolipids (gangliosides) to a high degree (95%) and in addition provides a good depiction of neuronal structures. The incubation of ultrathin sections of carp brain, treated as described above, with the specific antibody Q211 against polar gangliosides gave first evidence for a specific labelling of these amphiphilic glycosphingolipids and their localization within the brain tissue.