MONDAY, April 15, 2002 (HealthDayNews) -- For the first time, scientists have produced images that show where in the brain and body a common solvent goes when it's inhaled -- or "huffed" -- by kids.
Scientists at the Department of Energy's Brookhaven National Laboratory had originally thought the solvent, called toluene, would go straight to the white matter of the brain. The images show, however, that the chemical first goes to the dopamine centers of the brain before settling in the fat areas -- or white matter.
The study and the images appear in the April 26 issue of Life Sciences.
Toluene, one of the most common industrial solvents, is found in paints, glues and other household products. Like many other chemical solvents, it primarily affects the central nervous system and can cause serious, even fatal, kidney and liver damage, as well as heart failure.
Dopamine is a natural chemical that produces a "feel-good" effect and is activated by such drugs as cocaine. It's not clear from this study that toluene actually activated the dopamine. However, a previous study, also conducted at Brookhaven, indicates toluene probably does activate dopamine.
If toluene does elevate dopamine levels, this may explain its addictive properties.
"I'm convinced that toluene probably does release dopamine, and I'm convinced that it probably does get to the reward center of the brain," says Wilkie Wilson, a pharmacology professor at Duke University Medical Center and author of Just Say Know: Talking With Kids About Drugs and Alcohol. "The only issue is how rewarding is it in primates or humans, and I don't know an answer to that. It (the study) is a great first step."
Stephen Dewey, one of the study authors and a senior scientist at Brookhaven, says he has seen children in sixth grade on dialysis because of the damage inhalants did to their kidneys.
An alarming number of children are abusing or "huffing" chemical inhalants. In 2000, 2 million American children and teen-agers reported using inhalants at least once. According to the National Institute on Drug Abuse, 6 percent of U.S. children have tried inhalants by fourth grade and almost 20 percent by eighth grade. There's also concern inhalants can act as "gateway" drugs, leading to the use of other drugs.
Children were actually Dewey's impetus for undertaking this study. He has been doing drug education in schools since 1994.
"When I spoke in elementary schools, I was most likely to get a question about huffing," Dewey says. Many of these kids were inhaling common household and office items. Some would paint their fingernails with Wite-Out, then hold it under their noses. Others would paint rubber cement on their desks, roll it into a ball, and then walk around sniffing it. Disposable butane lighters and fingernail polish apparently did the trick as well, he says.
Despite the popularity of inhalants, relatively little is known about what they do to the body.
In their study, the Brookhaven chemists put a radioactive isotope into the toluene, then injected it into baboons and mice. A positron emission tomography (PET) camera picked up the radioactive signal, and produced images showing exactly where the toluene went in the body.
The chemical moved quickly into the dopamine sections of the brain, then spread out to the fat areas before leaving the body via the kidneys.
The redistribution to the white matter doesn't happen with other addictive drugs like cocaine, heroin and nicotine. It also means toluene stays longer in the system, Dewey says.
"The actual body exposure to an inhalant is longer because it sequesters in the fat," Dewey says. "Unlike other drugs of abuse, what you'll find is that, while you may huff short-term, the exposure is probably much longer because the body will store it in the fat."
This is also the first time that scientists have been able to image a solvent in such a way. The technique may lead the way for more investigation into other solvents, including hair spray and cleaning fluids.
What To Do: Adults who want more information on inhalants should visit the National Institute on Drug Abuse (NIDA) or the National Inhalant Prevention Coalition. Kids can visit Mind
Over Matter, also from the NIDA.
