EXPERIMENTAL ESTIMATION OF ADDICTIVE POTENTIAL OF A MIXTURE OF ORGANIC-SOLVENTS

In the present study we investigated in rats the reinforcing propertie s of glue vapours which are a mixture of four organic solvents (toluen e 25%, benzine fraction 37%, ethyl acetate 31% and methylene chloride 7%). This mixture is used as a glue thinner and is a very popular amon g glue-sniffing children. Immediately after inhalation at a concentrat ion of 7200 ppm, the glue vapours increased locomotor activity in the open field and response rate of self-stimulation in the lateral hypoth alamus. Contrary to classical drug abuse, glue vapours enhanced the th reshold current of self-stimulation. While the response rate of self-s timulation decreased to the control level 30 min after inhalation, the threshold current was still enhanced. Increasing the concentration of the vapours produced a decrease in response rate of self-stimulation and locomotor activity. When glue vapours were inhaled at a concentrat ion of 14 400 ppm and higher, the response rate of self-stimulation wa s completely suppressed. The discriminative stimulus effects of the gl ue vapours appeared to be similar to those of general anaesthetics suc h as ether and pentobarbital. At vapour concentrations of 7200 and 14 400 ppm, conditioned place preference was established. The ability of solvents to reinforce conditioning in the place preference paradigm an d to activate the brain reward system in intracranial self-stimulation experiments may be useful for predicting the addictive potential of i nhalants.