Effects of linalool on extinction of mouse operant behaviour

Linalool is an enanitomer monoterpene compound identified as the pharmacologically active constituent in a number of essential oils and has been reported to display anxiolytic properties in humans and in animal models and to exert both GABAergic and glutamatergic effects. In Experiment 1 linalool (100, 200, and 300, i.p.) had no significant effects compared with saline in an activity tracker with C57BL/6j mice. Experiment 2 assessed the effects on operant extinction with mice of chlordiazepoxide at a dose (15 mg/kg, i.p.) previously shown to facilitate extinction, and the same doses of linalool, compared with saline. Linalool had a dose-related facilitatory effect on extinction. While the effects of the highest dose of linalool most closely resembled the effects of chlordiazepoxide, the pattern of results suggested that linalool may affect both the acquisition of extinction learning, which is influenced by glutamatergic processes, and the expression of extinction, known to be affected by GABAergic agents such as chlordiazepoxide.