The present invention pertains to methods to promote outgrowth of, or extension across a substrate of, neuronal cells by inhibiting the interaction between the cytoplasmic tail of the L1-CAM cell surface adhesion molecule and the cytoskeletal protein ankyrin. The invention also pertains to a method to treat diseases characterized by axonal damage such as spinal cord injury, traumatic brain injury, stroke, and neurodegenerative disease by administration of novel peptides that inhibit the binding of the L1-CAM cytoplasmic tail to ankyrin, and to pharmaceutical compositions comprising such peptides. The invention further pertains to a method of blocking calcium flux to protect against neural cell death following stroke or traumatic head injury.