Immunocytochemical staining for ganglioside GD3 (II3 alpha(Neu Ac alph
a 2-8 NeuAc)-LacCer) in the choroid plexus of the adult rat brain was
carried out. A peroxidase reaction product for GD3 was predominantly p
resent along the surface of microvilli of the choroidal cells, suggest
ing that ganglioside GD3 may be concerned with the formation or secret
ion of the cerebrospinal fluid.