Ta3a is active at NaV channel isoforms, shifts the current-voltage plot to the left, and impairs inactivation of NaV1.7 channels by whole cells. Credit: Journal of Biological Chemistry (2024). DOI: 10.1016/j.jbc.2024.107757
Researchers at the University of Queensland have discovered how ant venom works by measuring electrical currents passing through individual channels in cells to understand how it causes pain.
Dr Angelo Keramidas from UQ’s Institute of Molecular Bioscience led a team that studied the powerful sting of the West African ant (Tetramorium africanum).
“This ant sting causes a cacophony of painful symptoms, not only intense, prolonged pain with redness and inflammation at the site of the sting, but also excessive sweating and goosebumps,” said Dr. Keramidas.
“We identified the characteristics of this toxin using electrophysiology and pharmacology, with equipment so sensitive that it can record electrical currents passing through unique sodium channels.”
The African ant species is confined to tropical countries in west and central Africa, from Guinea to Zaire, with pain symptoms similar to those of the Australian green-headed ant.
“We are also interested in whether this mechanism is found in the venom of other ants, as well as that of insects like wasps and bees,” said Dr Keramidas.
“This research is part of a larger project to understand how venom causes pain at the molecular level.
“This can help us develop new ways to treat acute and chronic pain.”
The team has previously shown that ant toxins bind to sodium channels, proteins embedded in the cell membrane of nerve cells.
“Through electrophysiology, we were able to see that the toxin binds to the sodium channel and hijacks the channel’s built-in activation mechanism, causing hyperactivity,” said Dr. Keramidas.
“There was a rush of negative ions attracted to the channel and a repulsion of positive ions which caused an amplification of sodium channel hyperactivity – a phenomenon we had never seen before.
“This hyperactivity causes a continuous triggering of the pain signal, explaining the ferocity of the ant sting.
“The venom activates several channels in the nerve cell membrane, and they remain active for a very long time and cannot be reset.
“We think this overstimulation eventually causes numbness at the sting site.”
The research was published in the Journal of Biological Chemistry.
More information:
Ashvriya Thapa et al, A mechanism of venom peptide-induced NaV channel modulation involving the interaction between fixed channel charges and ionic gradients, Journal of Biological Chemistry (2024). DOI: 10.1016/j.jbc.2024.107757
Provided by the University of Queensland
Quote: Electrophysiological study shows how ant toxin causes extreme pain (October 16, 2024) retrieved October 17, 2024 from
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