The heavy chain contains domains with several functions; it has the domain responsible for binding specifically to presynaptic nerve terminals, as well as the domain responsible for mediating translocation of the light chain into the cell cytoplasm as the vacuole acidifies. The light chain is a M27-family zinc metalloprotease and is the active part of the toxin. It is translocated into the host cell cytoplasm where it cleaves the host protein SNAP-25, a member of the SNARE protein family, which is responsible for fusion. The cleaved SNAP-25 cannot mediate fusion of vesicles with the host cell membrane, thus preventing the release of the neurotransmitter acetylcholine from axon endings. This blockage is slowly reversed as the toxin loses activity and the SNARE proteins are slowly regenerated by the affected cell.The seven toxin serotypes (A–G) are traditionally separated by their antigenicity. They have different tertiary structures and sequence differences. While the different toxin types all target members of the SNARE family, different toxin types target different SNARE family members. The A, B, and E serotypes cause human botulism, with the activities of types A and B enduring longest in vivo (from several weeks to months). Existing toxin types can recombine to create "hybrid" (mosaic, chimeric) types. Examples include BoNT/CD, BoNT/DC, and BoNT/FA, with the first letter indicating the light chain type and the latter indicating the heavy chain type.
$10.00 - $30.00 per unit) or by the area ($200–1000) and depends on expertise of a physician, clinic location, number of units, and treatment complexity.Insurance
Botox for medical purposes is usually covered by insurance if deemed medically necessary by your doctor and covers a plethora of medical problems including overactive bladder (OAB), urinary incontinence due to neurologic conditions, headaches and migraines, TMJ, spasticity in adult patients, cervical dystonia in adult patients, severe axillary hyperhidrosis (or other areas of the body), blepharospasm, upper or lower limb spasticity.Migraines
For migraine induced headaches the FDA-recommended dosage is 155 units and costs between $300 to $600 per treatment out of pocket when covered by insurance.Hyperhidrosis
Botox for excessive sweating is FDA approved.Cosmetic
Standard areas for aesthetics botox injections include facial and other areas that can form fine lines and wrinkles due to every day muscle contractions and/or facial expressions such as smiling, frowning, squinting, and raising eyebrows. These areas include the glabellar region between the eyebrows, horizontal lines on the forehead, crows feet around the eyes, and even circular bands that form around the neck secondary to platysmal hyperactivity. Bioterrorism
Botulinum toxin has been recognized as a potential agent for use in bioterrorism. It can be absorbed through the eyes, mucous membranes, respiratory tract, and non-intact skin. The effects of botulinum toxin are different from those of nerve agents involved insofar in that botulism symptoms develop relatively slowly (over several days), while nerve agent effects are generally much more rapid.