Objective measurement of human feelings is essential for the development of products and technologies to reduce stress. Therefore, sensitive indices of stress are sought to evaluate even weak stress. Since the sympathetic nervous system responds sensitively to stress, we searched for substances in saliva which are related to the activity of the nervous system. The resulting chromogranin A (CgA) is a major protein in adrenal chromaffin cells and adrenargic neurons. CgA and catecholamines are co-released into an extra-cellular environment. We measured changes in the concentrations of CgA, catecholamines and cortisol in saliva and plasma of male volunteers with exposure to stress. We found a prompt elevation in salivary CgA level and a delayed increase in salivary cortisol level with psychosomatic stresses applied by oral presentation in front of audience and car driving. After exercise , however, the CgA level did not change though the plasma catecholamine level increased immediately. These results suggest that salivary CgA may be a sensitive and promising index for psychosomatic stress. Salivary CgA, a novel biochemical index of stress, is expected to allow more precise evaluation of human feelings in various situations.
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