Brain peptide may block morphine’s effects

Press, 24 April 1984, Page 36

Brain peptide may block morphine’s effects

NZPA-AP Washington A recently isolated brain chemical may play a key role in morphine losing its effectiveness as a pain killer after continued use, researchers have reported. If a convenient way can be found to block the action of this chemical, then the effectiveness of morphine as a valuable pain killer will be enhanced. Dr Hsiu-ying Yang of the National Institute of Mental Health said she and her colleagues, Dr Erminio Costa and Dr Jian Tang, have found a chemical called a peptide that neutralises the pain-killing ef-

feet of morphine. The peptide had been found in the brains of rats and cows, and a similar substance almost certainly existed in human brains as well, she said. Dr Yang said this peptide appeared to be released in the brain when morphine was administered, decreasing the analgesic effects of the drug as the treatment increased. She told a seminar that a substance which counteracted a similar peptide, when injected directly into an animal brain, prolonged the effects of morphine. The researchers found

that a drug made in Italy and used widely outside the United States to treat stomach ulcers did inhibit some of the peptide’s activity when tested in rats. However, the drug, proglumide, did not block all the anti-morphine effects and scientists were looking for a better peptide-blocker. Dr Yang said her group recently purified the analge-sic-inhibiting peptide and is now determining its molecular structure. Once more is known about the peptide, it should be easier to find something that more effectively counteracts it, she said.