HISTOCHEMICAL CHARACTERIZATION OF LECTIN BINDING IN MOUSE CEREBELLUM

Eight fluorescein-isothiocyanate-conjugated lectins differing from each other in carbohydrate binding specificities have been used to reveal qualitative differences in carbohydrate composition among the various cell types of the early postnatal and adult cerebellar cortex, cerebellar deep nuclei and medulla. By treating unfixed frozen tissue sections with unconjugated lectin in the presence of excess hapten sugar and subsequently staining with fluorescein-isothiocyanate-conjugated lectin in the presence of bovine serum albumin, carbohydrate specific staining was observed for all of the lectins studied. Lectin binding was selectively inhibited by appropriate hapten sugars. For several lectins (wheat germ agglutinin, Ricinus communis agglutinins and Lens culinaris agglutinins) complex carbohydrates were required for inhibition of staining. In the adult cerebellum, concanavalin A intensely stained the soma of granule cells, synaptic glomeruli and the cytoplasm of Purkinje cells, while the molecular layer and white matter were relatively unstained. Wheat germ agglutinin heavily labeled the soma of granule cells, synaptic glomeruli, parallel fibers of the molecular layer, and the nuclear membrane of Purkinje cells, and weakly labeled the white matter. Ricinus communis agglutins (m.w. 60,000 and 120,000) intensely stained the soma of granule cells, synaptic glomeruli, parallel fibers in the molecular layer, the cytoplasm of Purkinje cells, and the white matter. None of the above lectins stained Purkinje cell dendrites. Lens culinaris lectins A and B stained the soma of granule cells, synaptic glomeruli, the cytoplasm of Purkinje cells, Purkinje cell dendrites, and white matter. In the 5- and 12-day-old postnatal cerebellum, concanavalin A stained the molecular layer more strongly than in the adult. Concanavalin A, wheat germ agglutinin and Lens culinaris lectins moderately stained cell cytoplasm in the external and internal granule layers, but the external granule cell layer was heavily labeled with both Ricinus communis lectins. With the soybean agglutinin, weak staining of the molecular layer and synaptic glomeruli was detected in young cerebellum, in contrast to adult tissue where no staining was observed. No labeling of the young or adult cerebellum was observed with Ulex europaeus agglutinin I. The specific patterns of staining with different lectins probably reflect the different carbohydrate compositions of the various cell types and perhaps of the intercellular matrix. © 1979.