Receptors to agglutinin from Dolichus biflorus (DBA) at the synaptic basal lamina of rat neuromuscular junction. A histochemical study during development and denervation.

The binding of agglutinin from Dolichus biflorus (DBA) and other lectins (Concanavalin A, agglutinin from wheat germ and lectin from Bandeiraea simplicifolia) to synaptic and extrasynaptic portions of the basal lamina of muscle fibers, was studied with histochemical methods. In rat muscle, DBA-binding is specifically detected at the basal lamina of neuromuscular junction. However, long-term (6 months) denervated end-plate in adult rat muscle failed to bind DBA. During normal development, synaptic DBA receptors appear later than acetylcholine receptors or acetylcholinesterase at the rat neuromuscular junction. Generalized DBA-binding to motor end-plates is first visualized in 3-day-old rats, but section of sciatic nerve in 1-day-old rats prevents the appearance of synaptic DBA-binding on the leg end-plates. It is suggested, therefore, that the synaptic DBA receptors could be related to the postnatal stabilization of rat neuromuscular synapses.