Beyond BOTOX: advantages and limitations of individual botulinum neurotoxins.

Botulinum neurotoxins are the most potent toxins designed by nature. They are produced by Clostridium bacteria to cause long-lasting paralysis and death. However, in the past century one member of the botulinum family--botulinum neurotoxin type A--has been put to good use, and is now widely employed in clinical neurology and, even more often, in beauty clinics. This article will critically assess the value of individual members of the botulinum family for experimental neuroscience and medicine. The seven botulinum neurotoxins all act by targeting the same vesicle fusion machinery, and yet they cause paralysis of different durations. The distinct behaviors of botulinum neurotoxins will be discussed, with the aim of highlighting advantages and limitations for their future exploitation.