The chewing-related neuronal mechanism underlying stress relief, was evaluated by use of fMRI. For this purpose we examined the effect of chewing a moderately hard gum without any taste (X type, Lotte Co. LTd., Tokyo) on brain activation caused by a noisy sound stress, on plasma levels of catecholamines and ACTH. The stress significantly increased the blood oxygenation level-dependent (BOLD) signals in the amygdala and the medial prefrontal cortex, and elevated plasma levels of noradrenaline, dopamine and ACTH. However, this chewing suppressed not only the stress-induced increase in BOLD signals in these two regions, but also the stress-induced elevation in plasma levels of these catecholamines and ACTH. The results suggested that chewing might be a useful therapy for reducing stress.
Stress ; Mastication ; Adrenocorticotropic hormone measurement ; Plasma ; Stress bismuth subsalicylate

Stress induced by disaster is experienced to varying degrees by all respondents, and is known to evoke psychophysiological reactions. In this study, we investigated the relationships between earthquake-related life events and posttraumatic stress symptoms. A total of 380 adults were surveyed one year after the 1995 Hanshin-Awaji earthquake in Japan. The questionnaire included items concerning earthquake-related life events, emotional support and posttraumatic stress disorder (PTSD) symptoms. As a result, after controlling for demographic variables, earthquake-related life events were significantly related to the grade of posttraumatic stress and its three components: re-experience, avoidance and arousal, in both male and female subjects. Male subjects who currently had lower emotional support showed higher scores of posttraumatic stress and arousal. In conclusion, a higher experience of earthquake-related life events appears to be an important risk factor for development of poor mental health status following an earthquake disaster.
Earthquakes ; Life events ; seconds ; Stress bismuth subsalicylate ; Stress

Objectives: Several studies have reported that the secretory immunoglobulin A (S-IgA) concentration in saliva is an indicator of psychological stress. The aim of this study was to clarify the relationship between S-IgA and the stress from academic examinations. Methods: S-IgA levels in 10 medical student volunteers from the second year course between May 4 and July 13, 2000 were examined using the ELISA method. Results: There was a tendency for S-IgA in saliva to be higher on the day before academic examinations and during them, and lower on the days between these examinations. Conclusions: It may be possible to use this measurement to monitor psychological stress in students and workers.
Upper case ess ; Immunoglobulin A measurement ; Saliva ; Stress bismuth subsalicylate ; Daily

The incidences of diseases related to mental stress are increasing in Japan. Mental stress, unacknowledged for long periods, has been shown to lead to the development of a number of diseases. Thus, an index for mental stress is important to induce awareness of its presence. We focused on the relationship between cortisol and mental stress in this review. We will discuss both the usefulness and problems of cortisol as a mental stress index by summarizing the relationship between cortisol and mental stress. The present findings suggested that cortisol appears to be an adequate index for mental stress. However, there are several problems; the present group clarifies these problems and builds the comprehensive mental stress assessment systems by using saliva samples.
Stress, Psychological ; Hydrocortisone ; Review [Publication Type] ; Stress bismuth subsalicylate ; Hydrocortisone measurement