美国科学60秒 SSS 2012-10-04(在线收听

 The black mamba is one of the world's most venomous snakes—its bite can kill a human in just half an hour. But along with deadly neurotoxins, the black mamba's venom has a special ingredient: a painkiller as potent as morphine. So says a study in the journal Nature. 

 
Researchers isolated proteins from mamba venom called mambalgins, and injected them into mice. Then they tested how long it took those mice to yank their paws out of water heated to a painful—but not damaging—115 degrees Fahrenheit. Turns out mice treated with mambalgins could take the heat for just as long as mice dosed with morphine, indicating the two drugs had similar pain-relieving effects.
 
Morphine works by binding opioid receptors, but mambalgins target a completely different pain pathway. Which is a good thing. Because they don't slow down breathing like opiates. And the body doesn't build up tolerance to mambalgins as fast as it does to morphine—meaning mambalgins could keep the pain away for longer. The French company Theralpha is now developing a drug from the venom. Just don't call it snake oil.
  原文地址:http://www.tingroom.com/lesson/sasss/2012/10/216259.html