Right now, you are walking around with a mouth full of extremely powerful, untested pharmaceuticals. Your saliva contains opiorphin, a painkiller that's about six times more powerful than morphine.
After so many decades spent prodding lab rats, one would think that there is nothing more to be discovered about the horrid little things, or how they relate to humans. One would be wrong. (What a fool one is!) In the early 2000s, scientists discovered that rat saliva contains sialorphin, a powerful painkiller. Rats are, in many ways, analogous to humans. Researchers began wondering if human saliva contained its own painkilling compound.
Enter opiorphin, a painkiller that seems to be both very effective and very simple. It works by preventing the breakdown of little chemicals called enkephalins. These chemicals stimulate the body's opiate receptors, which block pain signals. Liberal application of opiorphin keeps the body's own pain-blocking system going. Why such a powerful pain-killer is in saliva is up for debate. Possibly so many of our ancestors had to gnaw off their own feet when caught in traps that anything that kept them from having a coronary from the pain was an evolutionary advantage.
Speaking of pain, no painkiller's effectiveness can be determined without some good old-fashioned rat torture. Scientists compared rat reactions on opiorphin and on various quantities of morphine. Some tests were simple tail flicks. Others included having rats walk on upward-facing pins. (Torture is an exaggeration. The pins weren't sharp enough to cut the rats. The test was more like a "bed of nails." Enough small points are clustered together to support a body safely, if slightly uncomfortably.) The rats required about six times the amount of morphine as opiorphin to comfortably walk across the pins.
Opiorphin is a promising painkiller. Because it's already in our bodies, it could be used to cut down on bad reactions to painkillers, waning effectiveness, and addiction. On the other hand, it might preserve more than just enkephalins. If it prevents the breakdown of other chemicals in the body it could cause real problems if it were injected into someone in large quantities.