U-M Study Offers Clue To Addiction

ATLANTIC CITY, N.J. - Drug research at The University of Michigan Medical Center is beginning to throw light on how people get physically "hooked" on narcotics, such as morphine, heroin and codeine. Dr. Edward F. Domino, U-M professor of pharmacology, reported his research findings at the annual meeting of the Federation of American Societies for Experimental Biology. From their research work with rats, Domino and his associate, Ann Wilson, found that morphine affects the way acttylcholine is produced and used in the brain. Acetylcholine (ACh) is an essential substance in the nervous system. When normal rats were injected with morphine, the U-M researchers discovered that the ACh level in the rats' brains increased sharply. The ACh level in the brains of morphine-addicted, or "tolerant" rats, however, is about the same as for normal rats. When addicted rats were deprived of their accustomed dose of morphine, the ACh I level dropped abruptly. These findings suggest that morphine in some way stimulates both the production and utilization of ACh in the brain; this in turn provides a clues as to how the drug relieves pain, and why habitual use reduces its analgessic effectiveness and elads to physical dependence,