Anxiety-like behaviour and c-fos expression in rats that inhaled vetiver essential oil

Abstract

Vetiver essential oil (VEO) has been used in aromatherapy for relaxation. This study aimed to investigate the effects of VEO on an anxiety-related behavioural model (the elevated plus-maze, EPM) and immediate-early gene c-fos in amygdala, known to be involved in anxiety. Male Wistar rats were administered diazepam (1 mg/kg i.p.) for 30 min or inhalated with VEO (1%, 2.5% or 5% w/w) for 7 min prior to exposure to the EPM. Then, the effects of 2.5% VEO, the anxiolytic dose, on c-fos expression in amygdala were investigated. The rats given either 2.5% VEO or diazepam exhibited an anxiolytic-like profile in the EPM. VEO and diazepam significantly increased c-fos expression in the lateral division of the central amygdaloid nucleus (CeL). Therefore, the anxiolytic properties of VEO might be associated with altering neuronal activation in CeL. However, future studies are needed to investigate the precise mechanism of action of VEO.

Keywords::

• elevated plus-maze
• anxiety
• amygdala
• diazepam
• vetiver essential oils

Acknowledgements

The authors thank Dr R.N. de Almeida, Department of Physiology and Pathology/LTF, Universidade Federal da Paraiba, for suggesting the inhalation apparatus. They also thank Associate Professor S. Srisurapanon for advice concerning the corticosterone measurements and Miss K. Sae-Ung for technical assistance.

Additional information

Funding

This research was supported by a grant from TRF-MRG4980179 to Dr S. Saiyudthong.