March 19, 1998
NEW YORK (Reuters) -- A newly discovered, naturally occurring pain reliever may eventually be used to reduce the need for narcotic drugs in the treatment of chronic pain, a report suggests.  Researchers from the Kansai Medical University in Japan discovered a peptide -- a short protein -- that binds to cell membranes in the brain and spinal cord, according to a report in this week's issue of the journal Nature.  The peptide, known as nocistatin, blocked the sensation of painful stimuli when injected into animals, according to lead author Emiko Okuda-Ashitaka and colleagues.  The peptide appears to counteract a second molecule, known as nociceptin.  Nociceptin can amplify pain or enhance harmless stimuli into a painful sensation.  The two molecules have an opposite effect and although the administration of nocistatin can block nociceptin and alleviate pain, both compounds appear to have a common origin.  The findings may be useful for those who suffer from chronic pain syndromes and must take pain-killing drugs regularly.  "We have now identified two biologically active peptides, nociceptin and nocistatin, which are generated from the same precursor and play opposite roles in pain transmission," the authors wrote.
"Pharmacological opioid drugs have powerful analgesic effects in mammals.  The discovery of nocistatin may lead to the design of a novel analgesic devoid of the addiction and dependence associated with morphine."  The study was a collaborative effort with researchers from Osaka Medical College, the National University of Singapore, Osaka Bioscience Institute, and Peptide Institute, Inc.
SOURCE: Nature (1998;392:286-289)