Androctonus Australis Hector Insect Toxin (AaHIT)

AaHIT is a scorpion toxin which affects voltage-gated sodium channels. Four different insect toxins, namely AaHIT1, AaHIT2, AaHIT4 and AaHIT5, can be distinguished. It targets insects, except AaHIT4, which is also toxic to crustaceans and mammals. AaHIT specifically affects the voltage-gated sodium channels (VGSC) in insects. The effect of the toxin is excitatory since it shifts the voltage-dependent activation of the sodium channel to lower potentials. This mode of action is comparable to those of beta-toxins. The insect-specific trait most likely derives from the presence of a specific structured loop in the insect VGSCs. In spite of this, some research has shown that AaHIT4 specifically can affect the mammalian sodium channel by modulating alfa- and beta-type anti-mammal neurotoxins binding. The toxin induces muscle contractions of the insects leading to full-body paralysis.