Licking Your Wounds: A substance in saliva may kill your pain

So goes the old saying: "Lick your wounds." Well it may not be such a bad idea. Human saliva has been found to harbor some antibacterial substances and wound regeneration compounds. More recently a substance in saliva has been shown to control pain as well.

A team of neurobiologists lead by Dr. Catherine Rougeot at the Pasteur Institute in France has discovered a substance in human saliva that has analgesic/pain killing properties some six times more potent than Morphine. Thisneuropeptide compound in saliva has been named opiorphin and may lead to the development of a new class of pain killers. Incidentally , the researchers found that this compound not only has analgesic properties, but may also harbor anti-depressant properties. The human body produces endogenousneuropeptides to control pain. They are morphine like compounds in three classes called enkephalins, endorphins and dynorphins. These naturally produced neuropeptides attach to opioid receptors in our nervous system to inhibit pain. Short acting they are broken down by two enzymes called ectopeptidases. Pharmaceutical companies have developed drugs that mimic these neuropeptides in such drugs as morphine, opium, Fentanyl, Dilaudid and others. However, these very powerful drugs come at a cost of side effects and addiction.

Administration of opiorphin does two things, one, it attaches to the opioid receptors much like our natural endorphins and similarly synthetic morphine-like compounds, but it also inhibits the ectopeptidase enzymes thus allowing the pain killer neuropeptides to act longer. Tests by the French researchers on rats demonstrated that when injected into rats with controlled pain stimulated conditions, 1 milligram ofopiorphin per kg of body weight achieved the same analgesic effect as 3 mg of Morphine. There also appears to be less of an addictive nature to this natural substance. These are all good properties when developing new drug therapy for pain management.

While it is possible to extract or harvest this neuropeptide from human saliva, it is not necessary as the substance is simple enough to synthesize in the lab. A purified version of opiorphin could lead to the development of opiorphin-based pain medication in the near future. These findings were published in the Proceedings of the National Academy of Sciences.

Reference: Proceedings of the National Academy of Sciences (vol 103, p 17979)