A Novel Odour Attenuates The Physiological Effects of Chronic Stress

Peng Tjun Choy (2007). A Novel Odour Attenuates The Physiological Effects of Chronic Stress PhD Thesis, School of Biomedical Sciences, The University of Queensland.

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Author Peng Tjun Choy
Thesis Title A Novel Odour Attenuates The Physiological Effects of Chronic Stress
School, Centre or Institute School of Biomedical Sciences
Institution The University of Queensland
Publication date 2007-10
Thesis type PhD Thesis
Supervisor Noakes, Peter G.
Lavidis, Nickolas A.
Subjects 11 Medical and Health Sciences
Abstract/Summary Odours derived from plants have been used for centuries in aromatherapy for relieving stress, anxiety and depression. Most of the evidences for these remedies are anecdotal with minimal evidence based research. The aim of this study was to create an innovative stress relief odour to attenuate the physiological effects of chronic stress. Using an effective model for stress inducement, our laboratory has shown using concurrent stressors of social isolation and rat (predator) odour increases sympathetic neurotransmission in stress mice. The first part of this study, I used this model as a bioassay for stress inducement and evaluated 7 natural different plants derived green odours and various concentrations on their effects on stress where a control group (without treatment) is exposed to concurrent stressors while another group exposed to same concurrent stressors received treatment of 0.2 ml of odour sprayed onto beddings of animal cage 3 times daily for 2 weeks. Cis-3-hexen-1-ol and trans-2-hexenal are the more effective odours for attenuating effects of chronic stress. Upon completion of the first part of this project, I ranked the efficacy of these odours on their stress attenuation effects and proceed to stage two, where I used various combinations of the more effective stress relief odours and created concoctions of odours. I ranked these various odours combinations for efficacy and the most effective combination consist of three active chemical odours resulted in a novel odour PraescentTM. The third stage of this project is to investigate further the effect of Praescent on long term stress exposure. I exposed two groups of 4 weeks old postnatal inbred male BALB/c mice to concurrent stressors with one group receiving treatment of a combination of green odours, PraescentTM. Chronically stressed animals have increased levels of neurotransmitter release from the sympathetic varicosities when compared to minimal stressed animals. Stressed without treatment animals have a 105% increased in mean amplitude (131 ± 9.47 μV, n=30) compared to concurrent Praescent treated stressed animals (63.994 ± 3.75 μV, n=50; P < 0.00005). To corroborate these findings, I measured levels of stress hormone, corticosterone from plasma of these animals. Stressed animals had a significantly higher (3 times) in mean corticosterone plasma level (8.584 ng/ml, n=16) compared to concurrent Praescent treated stressed animals (2.078 ng/ml, n=14, P = 0.0329); hence Praescent has efficacious stress attenuating effects. The method of using odours to regulate the adverse effects of chronic stress is an ideal way managing stress as the olfactory system is the only sensory system that projects directly into the limbic system and the hypothalamus. The results obtained here are an important step toward human trials. We aim to use these results to further develop a novel therapeutic product for human use to combat the unwanted effects of chronic stress and reduce the prevalence of stress related illnesses. This is important not only for the individual but also for the prosperity of the nation as many of these health related cost will be reduce and productivity of the country increase.

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Created: Fri, 25 Mar 2011, 13:49:48 EST by Noela Stallard on behalf of Library - Information Access Service