Lectin cytochemistry of carbohydrates on cell membranes of rat cerebellum.

Wheat germ agglutinin (WGA), Ricinis communis agglutinin (RCA) and Lens culinaris (LC) lectins have been used to characterize carbohydrates of neuronal membrane systems in rat and chick cerebellum. WGA and RCA both label Golgi membrane cisternae on the side of the membrane facing the cisternal space but they do not label other elements of the granular and agranular endoplasmic reticulum (ER). WGA labels the plasma membrane generally and WGA binding sites are concentrated within the synaptic cleft and at specialized sites along the axolemma at the node of Ranvier. RCA labelling of plasma membranes is sparse. Neuraminidase treatment of tissue slices prior to lectin cytochemistry does not alter the Golgi membrane distribution of WGA and RCA binding sites and other ER membranes remain unlabelled. The plasma membrane staining with WGA is decreased and that with RCA is increased after neuraminidase pretreatment. The pattern of lectin labelling with LC resembles that seen with concanavalin A (con A) in that all elements of the ER within cell bodies label on the side of the membrane facing the cisternal space. A major difference when compared to con A labelling is that the hypolemmal cisternae lying adjacent to the plasma membrane of Purkinje cell axons and dendrites do not label with LC. Collectively, these results suggest that elements of the ER of Purkinje cells are heterogeneous with respect to their lectin binding properties in a manner which is consistent with the formation of more complex oligosaccharides on membranes of the cell periphery.