The burn of hot peppers and the searing pain of a spider bite may have a common cause. New research suggests that molecules in hot peppers and in a certain spider's venom target the same receptor on nerve cells.
Several years ago, scientists identified a channel on neurons that's opened by capsaicin, the molecule responsible for peppers' burn. Follow-up research showed that this channel is a member of a family of cell-surface receptors that sense both chemicals and temperature. When these channels are activated, ions flood into nerve cells and cause them to fire.
Although scientists have already studied components of spider venom that cause shock, paralysis, and death, little is known about the molecules that cause the pain. David Julius of the University of California, San Francisco and his colleagues wondered whether pain-inducing venom ingredients might activate the dual-purpose cell-surface channels.
The team purchased venoms collected from a variety of spider