Effects of fragrance administration on stress-induced prefrontal cortex activity and sebum secretion in the facial skin.
Although fragrances have long been known to influence stress-induced psychosomatic disorders, the neurophysiological mechanism remains unclear. We evaluated the effect of fragrance on the relation between the level of sebum secretion in the facial skin and the stress-induced prefrontal cortex (PFC) activity, which regulates the activity of the hypothalamic-pituitary-adrenal axis. Employing near infrared spectroscopy, we measured hemoglobin concentration changes in the bilateral PFC during a mental arithmetic task in normal adults (n=31), and evaluated asymmetry of the PFC activity in terms of the laterality index (i.e., [(right-left)/(right+left)]) of oxyhemoglobin concentration changes (LI-oxyHb). We measured the level of sebum secretion in the facial skin before the task performance. There was a significant positive correlation between the LI-oxyHb and the level of sebum secretion (r=+0.44, p=0.01). We selected the subjects who exhibited high levels of sebum secretion and right-dominant PFC activity for the study on the fragrance effect (n=12). Administration of fragrance for four weeks significantly reduced the level of sebum (p=0.02) in the fragrance group (n=6). In addition, the LI-oxyHb decreased significantly from 0.11+/-0.07 to -0.10+/-0.18 (p=0.01), indicating that the dominant side of the stress-induced PFC activity changed from the right to left side. In contrast, neither LI-oxyHb nor the levels of sebum secretion changed significantly in the control group (n=6). These results suggest that administration of fragrance reduced the level of sebum secretion by modulating the stress-induced PFC activity. The PFC may be involved in the neurophysiological mechanism of fragrance effects on systemic response to mental stress.
Tanida
Masahiro
M
Bioengineering Research Laboratories, Shiseido Life Science Research Center, Yokohama, Japan.
Katsuyama
Masako
M
Sakatani
Kaoru
K
D000328:Adult; D019341:Aromatherapy / Q000379:methods / Q000523:psychology*; D004292:Dominance, Cerebral / Q000502:physiology; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D005260:Female; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism / Q000503:physiopathology*; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D009812:Odorants; D009833:Olfactory Pathways / Q000187:drug effects / Q000502:physiology; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D017397:Prefrontal Cortex / Q000187:drug effects / Q000502:physiology*; D012629:Sebum / Q000378:metabolism*; D012867:Skin / Q000378:metabolism* / Q000503:physiopathology; D012903:Smell / Q000187:drug effects / Q000502:physiology; D013315:Stress, Psychological / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome