Researchers have discovered two painkillers produced naturally by the body, a finding that might yield hints for designing new medications to treat a variety of painful conditions.
Such drugs might work against pain that doesn't respond well to morphine, such as some pain from cancer, from diabetic nerve damage and from the disease shingles.Scientists have previously identified other natural painkillers, called endorphins, that act in the brain and spinal cord much like morphine.
So far, the new painkillers have shown promise in mice. One substance, dubbed nocistatin, (pronounced NO-suh-STAH-tin) is described in Thursday's issue of the journal Nature by Dr. Seiji Ito of the Kansai Medical University in Osaka, Japan, with colleagues there and elsewhere in Japan and Singapore.
"This is pretty big news," said Dr. Gavril Pasternak, who studies the biology of pain at the Memorial Sloan-Kettering Cancer Center in New York.
He and colleagues found the other new painkiller, which they call OFQ2.
Both painkillers are made from the same protein. Both act on the central nervous system, which includes the brain and spinal cord.
In the Nature paper, the Japanese scientists injected nocistatin along with a pain-producing substance into the spinal cords of mice. Normally, this second substance is so potent that mice find it painful when their flanks are stroked by a paintbrush. But nocistatin blocked its effect.