A new technique for post-embedding immunogold localization of vasopressin in the rat median eminence.

A modified cryosubstitution method is described which simultaneously preserves the ultrastructure and antigenicity of the osmium-sensitive neuropeptide vasopressin in rat median eminences. The organs were aldehyde-fixed, osmicated, and embedded in Epon. Thin sections were no longer needed to be etched and the titer of primary antiserum was near to the light microscopic level. Furthermore ice crystallization could not be observed.