Scorpion venom is a painkiller for the grasshopper mouse

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The bark scorpion is, according to Wikipedia, the most venomous scorpion in North America, wielding an intensely painful – and potentially lethal – sting that stuns and deters snakes, birds and other predators. People unfortunate enough to have experienced the sting say that it produces an immediate burning sensation, followed by prolonged throbbing pain that can last for hours.

But the grasshopper mouse is completely resistant to the bark scorpion's venom. In fact, it actively preys upon scorpions and other poisonous creatures. As the film clip below shows, it responds to the bark scorpion's sting by licking its paw for a second or two, before resuming its attack, then killing and eating the scorpion, starting with the stinger and the bulb containing the venom. Researchers have now established exactly why this is – paradoxically, the venom has an analgesic, or pain-killing, effect on the grasshopper mouse.

The animal's secret lies in two proteins, the sodium channels Nav1.7 and Nav1.8, which are found in a subset of sensory nerve fibres called nociceptors. These cells express numerous other proteins that are sensitive to damaging chemicals, excessive mechanical pressure, and extremes in temperature, and have fibres that extend from just beneath the skin surface into the spinal cord.

The sensor proteins relay these signals to Nav1.7 and Nav1.8, which then change their structure in response, so that their pores, which span the nerve cell membrane, open up, allowing sodium ions to flood into the cell. This causes the nociceptors to generate nervous impulses, which are transmitted along the fibre into the spinal cord. From there, the signals are relayed to second-order sensory neurons, which then carry the signals up into the brain, where they are interpreted as pain.

Written By: Mo Costandi
continue to source article at theguardian.com

8 COMMENTS

  1. Isn’t Evolution incredible?! The awe that I experience, as an ignorant layperson, by such humbling scientific “miracles” of the natural world like this mouse’s evolved resistance to venom, is far greater than anything I heard from the pulpit or while reading now-quaint Bible myths. Not the Ark, not the Garden of Eden, not the loaves and fishes; none of them can touch the magic of reality in terms of awe.

    • In reply to #1 by The Devout Atheist:

      Isn’t Evolution incredible?! The awe that I experience, as an ignorant layperson, by such humbling scientific “miracles” of the natural world like this mouse’s evolved resistance to venom, is far greater than anything I heard from the pulpit or while reading now-quaint Bible myths. Not the Ark, no…

      Patience is a virtue in the truest sense.

  2. Isn’t Evolution incredible?! The awe that I experience, as an ignorant layperson, by such humbling scientific “miracles” of the natural world like this mouse’s evolved resistance to venom, is far greater than anything I heard from the pulpit or while reading now-quaint Bible myths. Not the Ark, not the Garden of Eden, not the loaves and fishes; none of them can touch the magic of reality in terms of awe.

  3. And god couldn’t give these two proteins to us humans, the pinnacle of creation? If god was an engineer (and did exist), he would have been fired from his job a long time ago because of poor work performance. His boss would’ve look at us humans and said: “Hey, buddy. Is this the best you could do? You wasted a whole day on a crappy product like this? Both the hardware and the software have design flaws! I’m sorry but I have to let you go.”

    If anyone of us, engineer or not, had to power to create an intelligent species to put on this earth, we would easily do a better job than god.

  4. And god couldn’t give these two proteins to us humans, the pinnacle of creation? If god was an engineer (and did exist), he would have been fired from his job a long time ago because of poor work performance. His boss would’ve look at us humans and said: “Hey, buddy. Is this the best you could do? You wasted a whole day on a crappy product like this? Both the hardware and the software have design flaws! I’m sorry but I have to let you go.”

    If anyone of us, engineer or not, had to power to create an intelligent species to put on this earth, we would easily do a better job than god.

  5. I just printed this article and am using it as my opener in Advanced Biology today. We will talk about the proteins, how they are embedded in the membrane (hydrophobic hyrdophilic amino acids), any secondary messenger systems at play, ligands, and, finally EVOLUTION! I am jazzed up!

  6. This is an interesting adaptation to evolutionary pressure.
    Another example is the adaptation of particular caterpillars to feed on specific Mangroves which are poisonous to other species.

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