Narrator: This is Science Today. Researchers at the University of California, San Francisco, have been working with natural molecules, even venom from tarantulas, to better understand our pain pathway.
Julius: There's multiple reasons for that. One is that that's one of the jobs of our pain pathway — is to tell us about dangers and to protect the things that make those chemicals irritants.
Narrator: Dr. David Julius is an internationally-recognized figure in the field of thermosensation and pain.
Julius: Evolution has honed this collection of small and large molecules as a way to tickle our pain pathway to warn us about dangers and to protect the things that make those chemicals from predation. So, we've looked at those because they're really well-honed probes that allow us as scientists to zero in on things in the nervous system that are important or factors in the nervous system or molecules that are important for generating and regulating pain sensation.Narrator: Julius' lab previously identified and cloned the specific protein that causes burning in capsaicin, the molecule responsible for the spiciness of hot chili peppers. For Science Today, I'm Larissa Branin.