Modulating neuromuscular junction density changes in botulinum toxin-treated orbicularis oculi muscle.

Purpose: Botulinum toxin A is the most commonly used treatment for blepharospasm, hemifacial spasm, and other focal dystonias. Its main drawback is its relatively short duration of effect. The goal of this study was to examine the ability of corticotropin releasing factor (CRF) or antibody to insulin growth factor I-receptor (anti-IGFIR) to reduce the up-regulation of neuromuscular junctions that are associated with return of muscle function after botulinum toxin treatment.