New research from the University of Wisconsin (UW) School of Medicine and Public Health in Madison and Scripps Research Institute in LaJolla, Calif, shows how botulinum toxin uses a “navigational strategy” to latch onto nerve cells and inactivate them.
According to the research, the toxin attaches to a receptor on the surface of a nerve cell, then looks for a second type of receptor nearby. Once the toxin links to this second receptor, it enters the nerve cell and destroys a protein needed to deliver molecules that signal other nerve cells.
By blocking the signaling molecule, tiny amounts of botulinum toxin cause paralysis and even death through respiratory failure. The bacteria that make this toxin grow in soil and can be found inside cans of food that are improperly processed. Botulinum toxin is the reason that food from bulging cans is extremely dangerous.
According to botulinum toxin expert Edwin Chapman, PhD, UW-Madison professor of physiology and a Howard Hughes Medical Institute investigator, researchers have been working on the nerve-blocking ability of the seven individual botulinum toxins for decades and have been studying how the toxin enters neurons.
“This is the first paper to show in atomic detail the structure of botulinum neurotoxin touching the receptor on the surface of the neuron,” says Chapman. “The toxin has to bind to the neuron it wants to poison. This is a snapshot of the first stage of that poisoning.”
According to Chapman, better knowledge of botulinum toxin’s structure could enhance the growing number of treatments that use the toxin to block nerve signals. However, the medical treatments are not just for wrinkles, he notes.
“People with paralysis get spasms in the muscles that are shut off, and this could solve that,” says Chapman. “In a wide variety of dystonias, where spasms can cause really severe pain, this can relax the muscles.”
[newswise.com, December 13, 2006]