Snakes represent some of the deadliest venomous animals in the world, killing between 81,000 and 138,000 people each year, according to the World Health Organization. But in low doses, some of their toxins can produce analgesia.
For instance, a toxin from the black mamba (Dendroaspis polylepis) inhibits pain by blocking acid-sensing ion channels on the surface of pain-transmitting neurons in mice (Nature, 490:552-55, 2012). Another compound, taken from the venom of the king cobra (Ophiophagus hannah), likewise diminishes pain but acts in an unusual way. R. Manjunatha Kini of the National University of Singapore has found that so-called hannalgesin likely disrupts nitric oxide synthase in neurons, thereby reducing nitric oxide production, which is involved in pain. “There are many ways of skinning a cat, and there could be many ways to block pain,” says Kini.
Although both toxins helped launch companies looking to develop analgesics in recent years, neither progressed, ...
