Stress lowers the detection threshold for foul-smelling 2-mercaptoethanol

Abstract

Previous studies have reported enhanced vigilance for threat-related information in response to acute stress. While it is known that acute stress modulates sensory systems in humans, its impact on olfaction and the olfactory detection of potential threats is less clear. Two psychophysical experiments examined, if acute stress lowers the detection threshold for foul-smelling 2-mercaptoethanol. Participants in Experiment 1 (N = 30) and Experiment 2 (N = 32) were randomly allocated to a control group or a stress group. Participants in the stress group underwent a purely psychosocial stressor (public mental arithmetic) in Experiment 1 and a stressor that combined a physically demanding task with social-evaluative threat in Experiment 2 (socially evaluated cold-pressor test). In both experiments, olfactory detection thresholds were repeatedly assessed by means of dynamic dilution olfactometry. Each threshold measurement consisted of three trials conducted using an ascending method of limits. Participants in the stress groups showed the expected changes in heart rate, salivary cortisol, and mood measures in response to stress. About 20 min after the stressor, participants in the stress groups could detect 2-mercaptoethanol at a lower concentration than participants in the corresponding control groups. Our results show that acute stress lowers the detection threshold for a malodor.

The olfactory mucosa, first actor of olfactory detection, is sensitive to glucocorticoid hormone

“…For instance, one might hypothesise that detection of danger‐ or predator‐related odours might be more strongly affected by stress than that of neutral odours, that is odours without significance for survival or the maintaining of homeostasis. Interestingly, a small‐scale study in humans has shown that exposure to a mild stressor led to an increase in salivary cortisol, associated with an increased sensitivity to the foul smelling 2‐mercaptoethanol (Pacharra et al., ); in their own words, stress led to a state of ‘sensory hypervigilance’. Such modulation of sensory system by GR has also been observed also for taste (Fehm‐Wolfsdorf, Scheible, Zenz, Born, & Fehm, ; Ogawa et al., ) and audition (Fehm‐Wolfsdorf & Nagel, ).…”

HPA-axis and inflammatory reactivity to acute stress is related with basal HPA-axis activity

“…Second, day-to-day variation of basal cortisol activity based on short-term determinants such as the stress level of a particular day was documented in some studies (Adam et al, 2006; Wetherell et al, 2015b). But generally speaking, cortisol diurnal curve is a relative stable trait (Edwards et al, 2001; Elder et al, 2016; Pruessner et al, 1997a), and we tried to control for the effect of a particular day by asking the participants to take home samples on two consecutive days and using the average value.…”

Paradoxical olfactory function in combat Veterans: The role of PTSD and odor factors

“…A growing literature suggests that humans demonstrate augmented odor detection and sympathetic arousal (e.g. increased heart rate (HR) and skin conductance level (SCL)) in response to unpleasant and/or fear-related odors (Ahs, Miller, Gordon, & Lundstrom, 2013; Alaoui-Ismaili, Vernet-Maury, Dittmar, Delhomme, & Chanel, 1997; Bensafi et al, 2002a, 2002b), and that odor functioning and odor-related autonomic responses may be potentiated by acute stress (Krusemark & Li, 2012; Pacharra et al, 2016), high trait anxiety (La Buissonniere-Ariza, Lepore, Kojok, & Frasnelli, 2013), as well as anxiety disorders (Buron, Bulbena, & Bulbena-Cabre, 2015; Pause, Adolph, Prehn-Kristensen, & Ferstl, 2009; Wintermann, Donix, Joraschky, Gerber, & Petrowski, 2013). While the same might be predicted for stress-related disorders like posttraumatic stress disorder (PTSD), available data are limited by the fact that the vast majority of PTSD studies utilize auditory or visual stimuli to provoke symptoms and probe threat-related attentional or autonomic dysfunction (Ashley, Honzel, Larsen, Justus, & Swick, 2013; Bryant & Harvey, 1995; Felmingham, Rennie, Manor, & Bryant, 2011; Morgan, Grillon, Southwick, Davis, & Charney, 1996; Orr, Lasko, Shalev, & Pitman, 1995; Pitman et al, 2001; Pole, 2007; Wahbeh & Oken, 2013).…”