Additive effect of linalool on pentobarbital-induced sleep: possible involvement of GABAergic pathway

Linalool is a monoterpenoid compound that is a major component of the essential oils of some aromatic plants, including lavender. The anxiolytic and sedative effects of this compound have been previously reported. In this study, the effect of systemic administration of linalool and its possible mechanism of action on pentobarbital-induced sleep in mice was investigated.

In the first phase of this study, twenty-four mice in 4 separate groups received linalool at the doses of 10, 50 and 100 mg/kg sixty minutes before pentobarbital administration. Based on the results of the first phase of the study, 50 mg/kg was determined as the effective dose of linalool. In the next step, for determination of the involved mechanism in linalool hypnotic activity, diazepam as a GABA benzodiazepine receptor agonist, flumazenil a GABA benzodiazepine receptor antagonist, and WAY100635 a serotonin receptor antagonist were used.

Linalool, especially at the dose of 50 mg/kg, significantly and dose-dependently affected pentobarbital-induced sleep by increasing sleep time and decreasing sleep latency. Co-administration of diazepam with linalool showed synergistic effects and increased sleep time; however, by flumazenil administration these effects were reversed. Administration of WAY100635 did not cause any effect on the increasing effect of linalool on pentobarbital-induced sleep.

Linalool may possibly be effective on pentobarbital-induced sleep through the GABAergic pathway.