Circadian Variations of Salivary Stress Marker (Chromogranin A)

Abstract

Bruxism is a very common parafunction of the masticatory system. Currently, there is consensus about the multifactorial nature of the etiology of bruxism, and it is thought to be a central nervous system phenomenon related to stress and pain behavior rather than structural components. The relationship of bruxism and subjective stress has remained unclear. Recently, biomarkers have been used for assessing stress reaction such as chromogranin A (CgA) and cortisol. The level of CgA provides a sensitive and reliable index for evaluating psychological stress. We can have many reports about plasma CgA, but we can't have enough reports about salivary CgA. The aim of this study was to clarify circadian variation CgA in saliva. Four adults (1 male, 3 females) participated in this research. Subjects provided ten saliva samples. Saliva samples were collected in the morning (9 am) and in the night (21 pm), and every 3 h for 24 h. In addition, saliva samples were two-minute stimulated and unstimulated samples to measure CgA concentration, major salivary stress biomarkers. Unstimulated salivary CgA concentration varied more in time and individual difference than stimulated. Stimulated salivary CgA concentration was increased from 12 pm to 18 pm. Salivary CgA seemed to have a circadian variation with peak in the afternoon-night period and a nadir in the noon. With regard to circadian variations, salivary CgA concentrations, in particular stimulated saliva, hardly differ from plasma CgA. It was concerned that CgA concentration was influenced from a lot of factors.