"I was really intrigued by the fact that the mice, if they get stung, they just groom a little bit and then it's over," Rowe told LiveScience.
Clearly, the mice had evolved to handle the pain. To find out how, Rowe and her colleagues analyzed how the toxin acts on the nerve cells called nociceptors that pick up and relay pain to the mouse's brain.
Nerve cells communicate pain to the brain by translating stimuli into electric pulses. To do so, tiny channels in the cell membrane, called ion channels, open and close. One ubiquitous type of ion channel, the sodium/potassium channel, is present in cells throughout the body. This channel makes critical bodily functions, from breathing to muscle contractions, possible.
Typically, scorpion venom acts directly on sodium/potassium channels in nociceptors to create the sensation of pain. A specialized channel known as channel 1.7 is responsible for picking up the pain signal, whereas a channel called channel 1.8 carries it to the brain.
"They just turn (the nerve) on and send that signal to the brain," Rowe said.