Toluene On The Brain

Huffing. Bagging. Dusting. These are names for getting high by inhaling solvents like the toluene in spray paint. It's a type of substance abuse popular among middle schoolers, according to the National Institute on Drug Abuse (NIDA).

Neurophysiologist Arthur C. Riegel of the University of Arizona, neurochemist Agustin Zapata of NIDA, and their colleagues have now confirmed that toluene exposure increases release of the neurotransmitter dopamine in brain regions associated with reward and addiction (Neuropsychopharmacology, DOI: 10.1038/sj.npp.1301273). Prior studies suggested that toluene might not abide by the prevalent "dopamine hypothesis" for the basis of addiction, Riegel notes.

Using microelectrodes in rat brain tissue slices, the researchers observed that toluene, in drug-abuse-like amounts, selectively stimulates dopamine-releasing neurons in the ventral tegmental area (VTA). This area connects to a key neural reward area, the nucleus accumbens (ACB). Using tiny microdialysis tubes for delivering and drawing fluids from the VTA and ACB of living rats, the team was able to use high-performance liquid chromatography to directly detect and measure toluene-induced dopamine spikes.