The effects of inhaled bergamot and geranium essential oils on rat behaviour
Salvesen, G. J. (2009). The effects of inhaled bergamot and geranium essential oils on rat behaviour (Thesis). The University of Waikato, Hamilton, New Zealand. Retrieved from https://hdl.handle.net/10289/2784
Permanent Research Commons link: https://hdl.handle.net/10289/2784
The aim of this study was to evaluate the behavioural effects of inhaled bergamot, geranium and a combination of these oils in three novelty evoked tests of anxiety. Sixty adult Hooded Rats (Rattus norvegicus), with 10 rats randomly assigned to one of the 6 test groups; three essential oil treated groups, and three control groups. The essential oil groups consisted of bergamot, geranium and a combined group, i.e. the combination of bergamot and geranium oil. The control groups consisted of the odour and vehicle control, with the anxiolytic drug diazepam as a positive control. The behaviour of rats was assessed on the elevate-plus maze, open-field and social interaction test. Diazepam increased open arm entries and the time spent in the open arms, decreased time spent in closed arms and increased the number of head-dips and unprotected stretch-attends in the EPM. In the open-field diazepam increased immobility time, decreased ambulation, increased grooming activity and reduced the amount of time spent exploring the arena. Similarly, diazepam decreased the frequency of separations, sniffs, follows, crawls, passive and active interactions with test partners in the social interaction test. Bergamot, geranium and the combination of the two oils increased total arm entries in the elevated-plus maze. Bergamot increased locomotion and exploratory behaviour in open-field and decreased contact latency and increased passive and active interaction between the rat pairs in the social interaction test. Geranium decrease immobility and increase the time spent rearing in the open-field and also increased active interaction, i.e. partner sniffing and decreased the amount of time the rat pairs spent apart in the social interaction test. The combination of bergamot and geranium oil increased locomotion and the time spent in Zone2, and also increased exploratory behaviour, i.e. the frequency and duration of rears in the open-field. In the social interaction test, contact latency was shortened and active and passive interactions between rat pairs were increased by the combination of essential oils. The present study established that bergamot, geranium, and the combination of the two oils had a stimulating effect in the elevated-plus maze and an anxiolytic effect in the open-field and social interaction tests when inhaled. Furthermore the study also demonstrated that the combining of the oils had a potentiating effect on the anxiolytic properties of the single oils.
The University of Waikato
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