Outbreaks of botulism occur when people ingest foods contaminated with the neurotoxin. Botulinum toxin is the most potent known biological toxin. The toxin acts by interfering with presynaptic acetylcholine release at cholinergic nerve terminals. As a result, contraction of skeletal muscle fibers is prevented. Botulinum intoxicated muscle reacts almost identically to surgically denervated muscle.
Muscle paralysis is dose-dependent and reversible.
Dr. Scott is the first investigator to use injections of Botulinum-A toxin as a therapeutic agent in a clinical application. The toxin was injected into extraocular muscle to correct strabismus. Botulinum toxin has also been used for the treatment of blepharospasm and hemifacial spasm and spasmodic torticollis. Botulinum-A toxin is now available in 100 unit vials. This dosage of toxin is well below the LD 50 and can be used to manage muscle spasticity related to a variety of conditions.