Binding of horseradish peroxidase-alpha-bungarotoxin to axonal membranes at the node of Ranvier.

The binding of horseradish peroxidase (HRP)-labeled alpha-bungarotoxin (alpha-BuTx) was investigated in rat sciatic nerve. Activity was found to be localized to the axolemma of myelinated nerve fibers at the nodes of Ranvier. Activity was also seen in other regions of the axolemma where the myelin sheath was separated from the axon by enzymatic treatment. Pretreatment of nerves with native alpha-BuTx or curare blocked the binding of HRP-alpha-BuTx to the axonal membranes. This study demonstrates binding of alpha-BuTx to axonal membranes although the nature and significance of the toxin receptor is uncertain.