Differences in Salivary Alpha-Amylase and Cortisol Responsiveness following Exposure to Electrical Stimulation versus the Trier Social Stress Tests

Abstract

BackgroundCortisol is an essential hormone in the regulation of the stress response along the HPA axis, and salivary cortisol has been used as a measure of free circulating cortisol levels. Recently, salivary alpha-amylase (sAA) has also emerged as a novel biomarker for psychosocial stress responsiveness within the sympathetic adrenomedullary (SAM) system.Principal FindingsWe measured sAA and salivary cortisol in healthy volunteers after exposure to the Trier Social Stress Test (TSST) and electric stimulation stress. One hundred forty-nine healthy volunteers participated in this study. All subjects were exposed to both the TSST and electric stimulation stress on separate days. We measured sAA and salivary cortisol levels three times immediately before, immediately after, and 20 min after the stress challenge. The State (STAI-S) and Trait (STAI-T) versions of the Spielberger Anxiety Inventory test and the Profile of Mood State (POMS) tests were administered to participants before the electrical stimulation and TSST protocols. We also measured HF, LF and LF/HF Heart Rate Variability ratio immediately after electrical stimulation and TSST exposure. Following TSST exposure or electrical stimulation, sAA levels displayed a rapid increase and recovery, returning to baseline levels 20 min after the stress challenge. Salivary cortisol responses showed a delayed increase, which remained significantly elevated from baseline levels 20 min after the stress challenge. Analyses revealed no differences between men and women with regard to their sAA response to the challenges (TSST or electric stimulations), while we found significantly higher salivary cortisol responses to the TSST in females. We also found that younger subjects tended to display higher sAA activity. Salivary cortisol levels were significantly correlated with the strength of the applied electrical stimulation.ConclusionsThese preliminary results suggest that the HPA axis (but not the SAM system) may show differential response patterns to distinct kinds of stressors.

Increasing levels of saliva alpha amylase in electrohypersensitive (EHS) patients

“…It is known that these two physiological systems are independent in terms of neuronal circuits (Ulrich-Lai & Herman 2009) and that they may react differently to stressors. Some results suggested that the responses of the HPA and SAM systems differ depending on the type of stressor (Maruyama et al 2012). Moreover, salivary cortisol levels increase a few minutes after the initiation of stress (Droste et al 2008;Takai et al 2004), meaning that the HPA axis is relatively slower to respond while sAA levels are characterized by a rapid increase after a stress action, followed by a rapid decrease to normal levels after the cessation of the stressor (Speirs et al 1974;Takai et al 2004).…”

Reliability of Potential Pain Biomarkers in the Saliva of Healthy Subjects: Inter-Individual Differences and Intersession Variability

“…Since 1987, cortisol has been by far the most often used biomarker for acute pain [15]. It is generally considered a good biomarker because the level in saliva is unaffected by salivary flow rate, and it is resistant to degradation by enzymes and freezing [16].…”

Emerging Cardiovascular Risk Research: Impact of Pets on Cardiovascular Risk Prevention

“…Salivary cortisol has been used as a measure of the hypothalamus-pituitary-adrenal (HPA) axis response to stressors. Cortisol has large diurnal variation and may be associated with longer latency between the stressor and its response [28]. Elevated cortisol has been associated with risk of glucose intolerance, insulin resistance and type 2 diabetes [29] as well as endothelial damage, visceral fat accumulation, and impaired lipid metabolism in individuals with subclinical hypercortisolism [30].…”

“…The two measures capture different components of the stress response, and studies that have used the beta-blocker propranolol to suppress stress responses have shown an effect on sAA without affecting cortisol [31]. Compared to salivary cortisol, sAA represents short-term latency to stressors [28, 32, 33]. Its levels are also increased with exercise and caffeine intake and are correlated with norepinephrine levels during short duration response to psychological stress.…”