ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Thursday, July 18, 1996 TAG: 9607180057
SECTION: NATIONAL/INTERNATIONAL PAGE: A-3 EDITION: METRO
DATELINE: NEW YORK
SOURCE: Associated Press
A part of the brain that may be important in addiction reacts the same way to nicotine that it does to cocaine, heroin and other highly addictive drugs, researchers have found.
Their results provide further evidence of the power cigarettes wield over those unlucky enough to be hooked, and offer hints at how treatments might one day break nicotine addiction.
The results also provide some of the best physiological evidence yet suggesting that nicotine and cocaine addictions work in similar ways.
``It suggests from a neurobiological level that we're dealing with a real drug and a real brain effect,'' said George Koob of the Scripps Research Institute in La Jolla, Calif.
Earlier research has shown that nicotine stimulates the release of the neurotransmitter molecule dopamine in the brain.
The study by Italian researchers goes a step further by demonstrating that like most addictive drugs, nicotine causes dopamine to be released in a specific region known as the shell of the nucleus accumbens, which lies between the midbrain and the forebrain.
The shell links the amygdala, which is active during emotional experiences, and the core of the nucleus accumbens, which controls some aspects of movement. Taken together, the three areas are thought to be central in the process of addiction.
The research ``adds new weight to the conclusion that nicotine is indeed addictive,'' wrote Leslie Iversen of the University of Oxford in a commentary that appears with the study in the journal Nature on Thursday.
President Clinton and his GOP rival Bob Dole began trading barbs over tobacco last month. Dole opposes Clinton's attempt to regulate tobacco, and Dole has been dogged by criticism since he suggested in June that smoking wasn't necessarily addictive.
The new study ``is not a surprise, but I think it's very timely because of the current political debate,'' said David Self, a neuroscientist at the Yale University School of Medicine in New Haven, Conn.
The Italian study puts nicotine in a class with most well-known addictive drugs, including cocaine, morphine and amphetamines, said Gaetano Di Chiara, a neuroscientist at the University of Caglieri who led the research.
``The ability to stimulate dopamine transmission is a kind of mark, a kind of label which is common to all these drugs and substances,'' he said.
Dr. Di Chiara and three colleagues studied the effects of two nicotine doses on rats. They found that after the higher dose, the amount of dopamine produced in the shell of the nucleus accumbens increased significantly for 20 minutes. At the lower dose, the effect lasted about 10 minutes.
Nicotine also significantly increased brain activity in the nucleus accumbens after the higher dose, but not in 36 other brain areas the researchers monitored.
Those results suggest that some of the methods currently used to treat cocaine addiction might work for smokers.
``I've often argued that smoking cigarettes is not different from smoking cocaine,'' said Koob, who was not involved in the study.
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