The Alleviating Effects of Plant Derived Chemicals on Stress

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A presentation as part of our journal club.

Plant derived chemicals such as lavender, sandlewood and so on, have long been utilised as holistic relaxants in aromatherapy and complementary medicine.

But is there more to plant derived chemicals then meets the eye?

Overviewing the following papers;
- Alleviating Effects of Plant-Derived Fragrances on Stress-Induced Hyperthermia in Rats
- Attenuation of Stress-Induced Elevations in Plasma ACTH Level and Body Temperature in Rats by Green Odour

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  • CRH corticotropin RH. Need to change arrows for stress vs. Green odour
  • until ACTH levels stabilised to presurgical levels.
  • Altho it is likely to match up with that of ACTH, it would have been good to measure the effect of green odour when applied at different times
  • Also the direction of air flow
  • The Alleviating Effects of Plant Derived Chemicals on Stress

    1. 1.
    2. 2. Smell and the Brain<br /><ul><li>Odorous substances, including plant-derived fragrances, induce various physiological, emotional, and behavioural responses in human and other mammalian species</li></li></ul><li>Smell and the Brain<br /><ul><li>Neuronal impulses conduct along the olfactory tract to: prepiriform cortex, limbic system, thalamus and much more
    3. 3. Complex interconnected networks are responsible for many behaviours:
    4. 4. eating, affective, sexual and reflexes like salivation (trigeminal n.)</li></li></ul><li>Plant Derived Chemicals<br /><ul><li>Have long been utilised as holistic relaxants in aromatherapy and complementary medicine
    5. 5. Only recently have their physiological mechanisms been investigated</li></ul>PraescentTMalpha-pinene<br /> trans-2-hexenalcis-3-hexen-1-ol<br />
    6. 6. Alleviating Effects of Plant-Derived Fragrances on Stress-Induced Hyperthermia in Rats<br />By Akutsuet al<br />Presented by Aaron Sparshott<br />
    7. 7. Introduction<br /><ul><li>Investigated the effects of exposure to plant-derived odours on the autonomic and behavioural responses to novel environment in rats.
    8. 8. A transient increase of body temperature has been shown to be a typical and reproducible autonomic response to various physical as well as psychological stressors.
    9. 9. This response is often referred to as stress induced hyperthermia or emotional fever.</li></li></ul><li>What they did...<br /><ul><li>Rats were moved to a novel environment, by being transferred to an unfamiliar cage with a certain odour present.
    10. 10. 42 Rats in Total: Alpha-pinene, Lavender and Green Odourcages were each presented with 12 rats. Control Group ratswere placed back in original cage after handling.
    11. 11. Half of each odour group (n=6) except control, were exposed to solvent only.</li></ul>12<br />12<br />12<br />6<br />
    12. 12. Biosignals and Behaviour<br /><ul><li>Heart Rate and Temperature were monitored using a bio-signal transmitter implanted a week prior to experimentation.
    13. 13. Behavioural Analysis via video camera.
    14. 14. Sniffing
    15. 15. Rearing
    16. 16. Grooming
    17. 17. Resting
    18. 18. General Activity</li></li></ul><li>What they discovered...<br /><ul><li>Green Odour accelerated the declining phase of body temperature
    19. 19. Alpha-pinene suppressed stress-induced hyperthermia from the beginning</li></ul>Temperature Difference (oC)<br />Time (min)<br />
    20. 20. What they discovered...<br /><ul><li>Exposure to any of the three fragrances made no significant difference to Heart Rate</li></ul>∆ BPM<br />Time (min)<br /><ul><li>No significant differences in behaviour were observed as a result of any fragrance</li></li></ul><li>What does it mean?<br /><ul><li>Body Temperature rose as a result of being moved to a novel environment, reflected as a stress-induced hyperthermia response.
    21. 21. Previous studies have shown that stress-induced hyperthermia responses can be attenuated by pretreating the subject with centrally acting drugs such as;
    22. 22. noradrenalineβ receptor antagonist,
    23. 23. vasopressin,
    24. 24. prostaglandin inhibitors
    25. 25. 5-HT1A receptor agonists</li></li></ul><li>What does it mean?<br /><ul><li>In the present study, the rats were exposed to odorants without being given any severe stress, and the exposure to the green odour or the alpha-pinene was found to have alleviating effects of the stress-induced hyperthermia.
    26. 26. However it would appear that the mechanism of alleviation differs between the two odours.</li></li></ul><li>Other points of interest<br /><ul><li>Heart Rate might be a less sensitive parameter as compared with the Body Temperature for detecting the possible alleviating effects of fragrances on stress responses
    27. 27. ‘Sedative effects’ of lavender in human’s are more likely to be a psychological property rather than physiological.
    28. 28. Autonomic responses showed no significant difference to control
    29. 29. No observed change in behaviour.</li></li></ul><li>Summing Up<br />By recording autonomic and behavioural parameters from unrestrained rats, <br />Akutsu et al found that the <br />green odour and alpha-pinene<br /> have anti-stress potency, namely that they exerted alleviating effects on stress-induced hyperthermia.<br />
    30. 30. Attenuation of Stress-Induced Elevations in Plasma ACTH Level and Body Temperature in Rats by Green Odour<br />By Nakashima et al<br />Presented by Zoe Hutchins<br />
    31. 31. Introduction<br /><ul><li>Investigated the effect of green odour on plasma adenocorticotropic hormone (ATCH) and body temperature (Tb) of stress-induced rats</li></ul>GREEN ODOUR<br />trans-2-hexanal [0.03%]<br />cis-3-hexenal [0.03%]<br />
    32. 32. Stress Response:<br />Elevation of ACTH Level and Tb<br />Hypothalamus<br />Anterior Pituitary<br />Preoptic Centre<br />Olfactory Inputs<br />↓ Tb<br />↓ACTH<br />
    33. 33. Method - ACTH Measurements<br /><ul><li>Rats were relocated and immobilised via restraint for 2 hours
    34. 34. Control: immobilisation without green odour
    35. 35. Treatment: exposure to green odour at various times prior, during or following immobilisation
    36. 36. Blood was collected and assayed for ACTH either immediately following immobilisation or 2 days later.</li></ul>STRESS<br />1h<br />1h<br />½ h<br />0h<br />2h<br />4h<br />6h<br />48h<br />Immediate ACTH<br />Long-Lasting ACTH<br />
    37. 37. Results – ACTH Levels<br />Green odour [0.03%] decreased ACTH levels when applied during or following immobilisation.<br />
    38. 38. Method – Tb Measurements<br /><ul><li>Rats were implanted with telemetry transmitters and given 10 days to recover until ACTH levels stabilised.
    39. 39. Tb was recorded every 20 minutes for 3 consecutive days.
    40. 40. Treatment rats were exposed to green odour for 30 minutes during the beginning of the 2 hour immobilisation.</li></ul>Temperature Recording<br />10 days<br />Recovery<br />Stress (2hr)<br />Day 1<br />(Prior)<br />Day 3<br />(Post)<br />Device Implantation<br />Green Odour (½hr) <br />
    41. 41. Results – Tb Recording<br />Green odour [0.03%] decreased Tb immediately after stress and during the light phase of the following day.<br />
    42. 42. Methods - Weaknesses<br /><ul><li>During immobilisation the odorous paper was held 3cm from the nose of the rat, however when applied before or after immobilisation, the paper was placed in a corner of the cage.
    43. 43. Potential inconsistencies in the levels of green odour exposure the different groups received.</li></ul>IMMOBILISED<br />NON - IMMOBILISED<br />
    44. 44. Results Summary<br />GREEN ODOUR<br />↓ ACTH<br />↓ Tb<br />Immediately following stress & two days post-stress<br />When applied during or following stress <br />
    45. 45. Possible Mechanisms of Action<br /><ul><li>ACTH Levels
    46. 46. Hypothalamus & Catecholamine System
    47. 47. ↓ Fos in the Paraventricular Nucleus (PVN) down-regulating CRH secretion and subsequently ACTH
    48. 48. Tb Reduction
    49. 49. ↓ Sympathetic activity
    50. 50. ↓ ACTH and Glucocorticoids</li></ul>Further research is required to fully elucidate the physiologic mechanisms of green odour<br />
    51. 51. <ul><li>Due to current unpublished work the remainder of this presentation is not available to slideshare.
    52. 52. For more information regarding Praescent or SerenaScent go to</li>

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