Patterns of peanut agglutinin binding within the developing grasshopper central nervous system.

The location of peanut agglutinin (PNA) binding was investigated in the segmental ganglia of the developing grasshopper embryo. Neuronal processes were stained but cell bodies were not. The first appearance of PNA binding in development was associated with the first neurons to initiate axon outgrowth, the progeny of the MP2 cells. In the early stages of development the location of PNA binding was congruent with that of antibodies against horseradish peroxidase (HRP), which bind to neurons. In more advanced ganglia only a subpopulation of those neuronal processes that bound auti-HRP also bound PNA. The results suggest that PNA-binding sites are present only on those neuronal processes which are still developing and raise the possibility that these molecules may play a rôle in neurite outgrowth and navigation.