One scorpion, two venoms: Prevenom of Parabuthus transvaalicus acts as an alternative type of venom with distinct mechanism of action
AUTOR(ES)
Inceoglu, Bora
FONTE
The National Academy of Sciences
RESUMO
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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=298702Documentos Relacionados
- Scorpion venoms: taking the sting out of lung disease.
- Perinatal effects of scorpion venoms: maternal and offspring development
- Isolation and characterization of a novel lepidopteran-selective toxin from the venom of South Indian red scorpion, Mesobuthus tamulus
- Comparison between two methods of scorpion venom milking in Morocco
- Comparison of two purified toxic fractions from Mesobuthus eupeus scorpion venom