One scorpion, two venoms: Prevenom of Parabuthus transvaalicus acts as an alternative type of venom with distinct mechanism of action

Bora Inceoglu, Jozsef Lango, Jie Jing, Lili Chen, Fuat Doymaz, Isaac N Pessah, Bruce D. Hammock

Research output: Contribution to journalArticle

102 Scopus citations


Scorpion venom is a complex mixture of salts, small molecules, peptides, and proteins. Scorpions employ this valuable tool in several sophisticated ways for subduing prey, deterring predators, and possibly during mating. Here, a subtle but clever strategy of venom utilization by scorpions is reported. Scorpions secrete a small quantity of transparent venom when initially stimulated that we propose to name prevenom. If secretion continues, a cloudy and dense venom that is white in color is subsequently released. The prevenom contains a combination of high K+ salt and several peptides including some that block rectifying K+ channels and elicit significant pain and toxicity because of a massive local depolarization. The presence of high extracellular K+ in the prevenom can depolarize cells and also decrease the local electrochemical gradient making it more difficult to reestablish the resting potential. When this positive change to the K+ equilibrium potential is combined with the blockage of rectifying K+ channels, this further delays the recovery of the resting potential, causing a prolonged effect. We propose that the prevenom of scorpions is used as a highly efficacious predator deterrent and for immobilizing small prey while conserving metabolically expensive venom until a certain level of stimuli is reached, after which the venom is secreted.

Original languageEnglish (US)
Pages (from-to)922-927
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number3
StatePublished - Feb 4 2003


ASJC Scopus subject areas

  • Genetics
  • General

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