RECENT STUDIES ON MODE OF ACTION OF SCORPION NEUROTOXINS

The neuromuscular intoxication by scorpion venom may be due to its ability to act on exposed fibres or on muscles directly or through motor nerves. Since an intact nerve trunk appears to be impermeable to the venom, the venom makes contact with the nerve tissue at the exposed presynaptic terminals at the neuromuscular junction. The resulting muscular twitchings and fibrillations may be due to a stimulation of the release of the transmitter substance. It appears that scorpion neurotoxins (which are low molecular weight, thermostable, basic proteins), possess the general ability to depolarize excitable membranes. This is due to an increase in the sodium permeability of the resting membrane and reduction of the rate and amount of sodium inactivation. © 1969.