Characteristics of Salivary Chromogranin A as a Short-term Mental Stress Biomarker

Abstract

(OBJECTIVE) Recent psycho-physiological studies have revealed close relationships between human mental stress and secretion of hormones and/or immunological substances. However, a precise elaboration of fluctuations in the secretion of these biomarkers in the time series against stress is not yet clearly illuminated. In this study, we used Chromogranin A (CgA) as a possible biomarker of mental stress for 1) illustrating the precise stress-response in the time series, and 2) investigating a congruity of CgA as the biomarker for mental workloads. (METHOD) In the experiment, ten male university students were inscribed to conduct a simple and easy arithmetic task (T) for 36 minutes with intermission (I) in two different T/I schedule: (A) a set of 18 (T)-9 (I) was repeated 2 times and (B) a set of 6 (T)-3 (I) was repeated 6 times. It should be noted that the total task period and intermission period is the same in both experiment A and B. (RESULT) As a developing result, salivary CgA concentration depicted an increase during the tasks and decrease (recovering) during the intermissions, while such a change was significant and more remarkable in the experiment A. The difference in the rate of increase/decrease induced by the task/intermission was also observed. (CONCLUSION) The stress-response of CgA in the time series plausibly demonstrated the possible candidacy of CgA as a biomarker for a short-term mental workload. In addition such a difference in the increase/decrease rate or time-lag in the responses by loading/unloading of the mental stress would bring forth an apparent difference in observation, thus impairing the effectiveness of CgA as a stress marker, if the assessment of CgA were not close enough.