Inhaling glue, paint, cleaning fluids, and nail polish remover is regarded as a harmless entertainment of the homeless by many.
But scientists have proven that they can be as dangerous as standard drugs.
Toluene, the solvent in many of these substances, actions on our brains the same way as notorious cocaine and methamphetamine do.
Solvent abuse turns an individual prone for other drugs, favors depression and suicide, and irreversibly damages the brain, heart, kidney, and liver.
Solvents were thought to act on all brain regions, not targeting
a specific area, like standard drugs do.
But in 2002, neurologist Stephen Dewey of Brookhaven National Laboratory, in Upton, New York, and his team proved that toluene affects specific brain areas, like the reward center, which includes two main structures, the ventral tegmental area (VTA) and the nucleus accumbens (ACB).
Nicotine (from tobacco) and cocaine enhance a group of dopamine-releasing neurons in the VTA.
Dopamine is the brain's pleasure hormone situated into the VTA and the ACB.
The research showed that toluene provokes the neurons in the VTA to start firing, but it was not proven that it triggers the dopamine release.
That's why some came with the idea that maybe toluene acts on the brain using a dopamine-independent pathway.
To solve the puzzle, a team at the Oregon Health and Science University in Portland emerged rat brain portions in different toluene concentrations and discovered that lower concentrations were more powerful.
1 ml Molar or more proved ineffective, explaining why solvents are most potent when inhaled in small quantities.
Injecting small amounts of toluene into the brains of live rats, the team discovered that it released both VTA and ACB neurons, like other drugs do.
This research is "a really outstanding piece of work," said Dewey.
"Researchers should now investigate whether they can curb toluene addiction using compounds that block dopamine receptors."