Navigation Links
Grasshopper mice are numb to the pain of the bark scorpion sting
Date:10/24/2013

The painful, potentially deadly stings of bark scorpions are nothing more than a slight nuisance to grasshopper mice, which voraciously kill and consume their prey with ease. When stung, the mice briefly lick their paws and move in again for the kill.

The grasshopper mice are essentially numb to the pain, scientists have found, because the scorpion toxin acts as an analgesic rather than a pain stimulant.

The scientists published their research this week in Science.

Ashlee Rowe, lead author of the paper, previously discovered that grasshopper mice, which are native to the southwestern United States, are generally resistant to the bark scorpion toxin, which can kill other animals.

It is still unknown why the toxin is not lethal to the mice.

"This venom kills other mammals of similar size," said Rowe, Michigan State University assistant professor of neuroscience and zoology. "The grasshopper mouse has developed the evolutionary equivalent of martial arts to use the scorpions' greatest strength against them."

Rowe, who conducted the research while at The University of Texas at Austin, and her colleagues ventured into the desert and collected scorpions and mice for their experiments.

To test whether the grasshopper mice felt pain from the toxin, the scientists injected small amounts of scorpion venom or nontoxic saline solution in the mice's paws. Surprisingly, the mice licked their paws (a typical toxin response) much less when injected with the scorpion toxin than when injected with a nontoxic saline solution.

"This seemed completely ridiculous," said Harold Zakon, professor of neuroscience at The University of Texas at Austin. "One would think that the venom would at least cause a little more pain than the saline solution. This would mean that perhaps the toxin plays a role as an analgesic. This seemed very far out, but we wanted to test it anyway."

Rowe and Zakon discovered that the bark scorpion toxin acts as an analgesic by binding to sodium channels in the mouse pain neurons, and this blocks the neuron from firing a pain signal to the brain.

Pain neurons have a couple of different sodium channels, called 1.7 and 1.8, and research has shown that when toxins bind to 1.7 channels, the channels open, sodium flows in and the pain neuron fires.

By sequencing the genes for both the 1.7 and 1.8 sodium channels, the scientists discovered that channel 1.8 in the grasshopper mice has amino acids different from mammals that are sensitive to bark scorpion stings, such as house mice, rats and humans. They then found that the scorpion toxin binds to one of these amino acids to block the activation of channel 1.8 and thus inhibit the pain response.

"Incredibly, there is one amino acid substitution that can totally alter the behavior of the toxin and block the channel," said Zakon.

The riddle hasn't been completely solved just yet, though, Rowe said.

"We know the region of the channel where this is taking place and the amino acids involved," she said. "But there's something else that's playing a role, and that's what I'm focusing on next."

Some resistance to prey toxins in mammals has been found in other species. The mongoose, for example, is resistant to the cobra. And naked mole rats' eyes do not burn in pain when carbon dioxide builds up in their underground tunnels.

This study, however, is the first to find that an amino acid substitution in sodium channel 1.8 can have an analgesic effect.

Rowe said studies such as this could someday help researchers target these sodium channels for the development of analgesic medications for humans.


'/>"/>

Contact: Ashlee Rowe
roweashl@msu.edu
517-432-4468
University of Texas at Austin
Source:Eurekalert  

Related biology news :

1. New scorpion discovery near metropolitan Tucson, Arizona
2. Clemson hosting scientists who study devastating diseases
3. Paper-based device could bring medical testing to remote locales
4. Neuron claws in the brain enable flies to distinguish 1 scent from another
5. New Brain Supplement Focus Boost Launches, Boosting Alertness, Memory and Focus
6. Finally mapped: The brain region that distinguishes bits from bounty
7. FPC Awarded new Smartphone DW From Existing Prominent Asian OEM Customer for Launch With Leading US Operator
8. Funding for animal testing alternative
9. First update in a century in testing drugs for elemental impurities
10. CCNY chemists devise new way to prepare molecules for drug testing
11. With early, obvious benefit of a targeted cancer drug, should expensive clinical testing continue?
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Grasshopper mice are numb to the pain of the bark scorpion sting
(Date:5/16/2016)... --  EyeLock LLC , a market leader of iris-based ... IoT Center of Excellence in Austin, Texas ... embedded iris biometric applications. EyeLock,s iris authentication ... with unmatched biometric accuracy, making it the most proven ... platform uses video technology to deliver a fast and ...
(Date:4/28/2016)... , April 28, 2016 Infosys ... (NYSE: INFY ), and Samsung SDS, a global ... that will provide end customers with a more secure, fast ...      (Logo: http://photos.prnewswire.com/prnh/20130122/589162 ) , ... but it also plays a fundamental part in enabling and ...
(Date:4/19/2016)... UAE, April 20, 2016 The ... as a compact web-based "all-in-one" system solution for all ... fingerprint reader or the door interface with integration authorization ... access control systems. The minimal dimensions of the access ... into the building installations offer considerable freedom of design ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... 2016  Liquid Biotech USA ... a Sponsored Research Agreement with The University of ... from cancer patients.  The funding will be used ... with clinical outcomes in cancer patients undergoing a ... be employed to support the design of a ...
(Date:6/24/2016)... (PRWEB) , ... June 24, 2016 , ... While the ... such as the Cary 5000 and the 6000i models are higher end machines that ... the height of the spectrophotometer’s light beam from the bottom of the cuvette holder. ...
(Date:6/23/2016)... , June 23, 2016   Boston Biomedical ... novel compounds designed to target cancer stemness pathways, ... been granted Orphan Drug Designation from the U.S. ... of gastric cancer, including gastroesophageal junction (GEJ) cancer. ... designed to inhibit cancer stemness pathways by targeting ...
(Date:6/23/2016)... , ... June 23, 2016 , ... ... YM (Yeast and Mold) microbial test has received AOAC Research Institute approval 061601. ... microbial tests introduced last year,” stated Bob Salter, Vice President of Regulatory and ...
Breaking Biology Technology: