Toluene inhalation and anxiolytic activity: possible synergism with diazepam

Toluene exposures or injections of diazepam reinstated lever responses that had been suppressed by punishment in laboratory rats. When concentrations of toluene or diazepam that were ineffective or minimally effective in this paradigm were administered in combination, they produced a qualitatively similar effect which was much greater than the sum total of effects produced by the same amount of either substance alone. These observations suggest an anxiolytic action for toluene and a possible synergism between the two substances.