The Impact of Stressor Exposure and Glucocorticoids on Anxiety and Fear

Hassell, James E.; Nguyen, Kadi T.; Gates, Chloé A.; Lowry, Christopher A.

doi:10.1007/7854_2018_63

Cited by 12 publications

(4 citation statements)

References 310 publications

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“…Interestingly, this effect of M. vaccae was absent in mice exposed to CDR, suggesting that stress resilience effects of M. vaccae to promote proactive coping behavioral responses can be disrupted, through unknown mechanisms, by CDR. Contrary to our expectations, SD exposure increased, rather than decreased, cognitive performance in the OLM test, an observation that is consistent with previous studies demonstrating that acute exposure to stress or acute injections of glucocorticoids can enhance memory consolidation (for review, see Hassell et al, 2019b); however, this effect was only observed in M. vaccae-immunized mice that underwent CDR. Immunization with M. vaccae prevented stress-induced decreases in alpha diversity of the gut microbiome following CDR and stabilized the community-wide gut microbiome as measured by within-group beta-diversity.…”

Section: Discussionsupporting

confidence: 87%

“…In addition, we assessed the effects of M. vaccae, CDR, and SD on subsequent cognitive performance in the object location memory (OLM) test. Finally, we evaluated potential mediators and moderators of the effects of M. vaccae, CDR, and SD, including measures of alpha and beta diversity in the gut microbiome, the fecal metabolome, the host plasma metabolome, and serotonergic gene expression in the midbrain and pontine raphe complex, brain systems implicated in individual variability in vulnerability to anxiety-and depressive-like behavioral responses Hassell et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Effects of Immunization With the Soil-Derived Bacterium Mycobacterium vaccae on Stress Coping Behaviors and Cognitive Performance in a “Two Hit” Stressor Model

et al. 2021

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Previous studies demonstrate that Mycobacterium vaccae NCTC 11659 (M. vaccae), a soil-derived bacterium with anti-inflammatory and immunoregulatory properties, is a potentially useful countermeasure against negative outcomes to stressors. Here we used male C57BL/6NCrl mice to determine if repeated immunization with M. vaccae is an effective countermeasure in a “two hit” stress exposure model of chronic disruption of rhythms (CDR) followed by acute social defeat (SD). On day –28, mice received implants of biotelemetric recording devices to monitor 24-h rhythms of locomotor activity. Mice were subsequently treated with a heat-killed preparation of M. vaccae (0.1 mg, administered subcutaneously on days –21, –14, –7, and 27) or borate-buffered saline vehicle. Mice were then exposed to 8 consecutive weeks of either stable normal 12:12 h light:dark (LD) conditions or CDR, consisting of 12-h reversals of the LD cycle every 7 days (days 0–56). Finally, mice were exposed to either a 10-min SD or a home cage control condition on day 54. All mice were exposed to object location memory testing 24 h following SD. The gut microbiome and metabolome were assessed in fecal samples collected on days –1, 48, and 62 using 16S rRNA gene sequence and LC-MS/MS spectral data, respectively; the plasma metabolome was additionally measured on day 64. Among mice exposed to normal LD conditions, immunization with M. vaccae induced a shift toward a more proactive behavioral coping response to SD as measured by increases in scouting and avoiding an approaching male CD-1 aggressor, and decreases in submissive upright defensive postures. In the object location memory test, exposure to SD increased cognitive function in CDR mice previously immunized with M. vaccae. Immunization with M. vaccae stabilized the gut microbiome, attenuating CDR-induced reductions in alpha diversity and decreasing within-group measures of beta diversity. Immunization with M. vaccae also increased the relative abundance of 1-heptadecanoyl-sn-glycero-3-phosphocholine, a lysophospholipid, in plasma. Together, these data support the hypothesis that immunization with M. vaccae stabilizes the gut microbiome, induces a shift toward a more proactive response to stress exposure, and promotes stress resilience.

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Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Effects of Immunization With the Soil-Derived Bacterium Mycobacterium vaccae on Stress Coping Behaviors and Cognitive Performance in a “Two Hit” Stressor Model

et al. 2021

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“…The decreased searching for the open arm reflected an increase in anxiety-like behavior due to an aversive experience, as is also seen when faced with another threatening situation [ 42 ]. These results suggested that increased depression- and anxiety-like behaviors were associated with changes in CORT and monoamine levels in various brain regions [ 43 ]. However, our results indicate that MYR administration can help restore the SPS-induced depression and anxiety-like behaviors.…”

Section: Discussionmentioning

confidence: 99%

Myricetin Inhibited Fear and Anxiety-Like Behaviors by HPA Axis Regulation and Activation of the BDNF-ERK Signaling Pathway in Posttraumatic Stress Disorder Rats

Sur

Lee

2022

Evidence-Based Complementary and Alternative Medicine

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Posttraumatic stress disorder (PTSD) is a stress-related psychiatric or mental disorder characterized by experiencing a traumatic stress. The cause of such PTSD is dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and imbalance of monoamines. Myricetin (MYR) is a common natural flavonoid that has various pharmacological activities. We investigated the effects of MYR on fear, depression, and anxiety following monoamine imbalance and hyperactivation of HPA axis in rats exposed to a single prolonged stress (SPS). Male rats were dosed with MYR (10 and 20 mg/kg, i.p.) once daily for 14 days after exposure to SPS. Administration of MYR reduced freezing responses to extinction recall, depression, and anxiety-like behaviors and decreased increase of plasma corticosterone and adrenocorticotropic hormone levels. Also, administration of MYR restored decreased serotonin and increased norepinephrine in the fear circuit regions, medial prefrontal cortex, and hippocampus. It also increased the reduction in the brain-derived neurotrophic factor (BDNF) and tropomyosin-related kinase B mRNA expression and the ratio of p-ERK/extracellular signal-regulated kinase (ERK) in the hippocampus. Thus, MYR exerted antidepressant and anxiolytic effects by regulation of HPA axis and activation of the BDNF-ERK signaling pathway. Finally, we suggest that MYR could be a useful therapeutic agent to prevent traumatic stress such as PTSD.

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“…There is now evidence that specific stressors may elicit specific responses, and may activate different brain systems by using specific pathways within the central nervous system [3]. Equally observed is the fact that stressors are selective pressures from the physical and social environment that threaten or challenge an organism and elicit compensatory response patterns [6]. It can equally be a state of disharmony or threatened homeostasis, evoking physiologically and behaviorally adaptive responses that can be specific to the stressor or generalized and nonspecific and that usually occur stereotypically, producing a "nonspecific" stress syndrome when the threat to homeostasis exceeds a threshold [7].…”

Section: Introductionmentioning

confidence: 99%

Effect of Short and Long Term Restraint Stress on the Histology of Liver, Kidney and Suprarenal Gland in Albino Mice during Postweaning Period

Said

Okafor

Haji

et al. 2021

JPRI

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On exposure to stress and for the sake of survival, cells make adjustments with the changes in their environment to the physiologic needs and non-lethal pathologic injury. When the environmental changes are greater than the capacity of the cell to maintain normal homeostasis the cell undergoes acute cell injury. If the injury or insult is removed on time, or the cell can adapt and withstand the injury, the term reversible injury is applied. The processes of adaptation include decreasing or increasing their size, increasing their number, or changing the pathway of phenotypic differentiation of cells. In the present study, albino mice of postweaning age of BALB C strain (21 days old) were exposed to short term (5 days) and long term (21 days) restraint stress to evaluate any histological changes in the kidney, liver, and suprarenal gland. Mice subjected to long term stress showed in the kidney degeneration of the cells of the glomerulus and the convoluted tubules. In the liver, they showed congested sinusoids and the presence of some fatty change, whereas in the suprarenal gland mice subjected to 21 days of stress showed moderate hypertrophy and hyperplasia of the adrenal cortex with the presence of moderate lipoid deposits when compared to controls. The overall effect on short term stress was mild when compared to exposure to 21 days stress Long term stress causes degeneration in hepatic cells, infiltration in the liver, degeneration of glomerulus, Bowman’s capsule, convoluted tubules in the kidney which could lead to nephrotoxicity. In the suprarenal gland, long term stress induces hypertrophy of the adrenal cortex. These morphological changes can explain the impaired immunity which develops in organisms that are exposed to chronic stress.

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The Impact of Stressor Exposure and Glucocorticoids on Anxiety and Fear

Cited by 12 publications

References 310 publications

Effects of Immunization With the Soil-Derived Bacterium Mycobacterium vaccae on Stress Coping Behaviors and Cognitive Performance in a “Two Hit” Stressor Model

Effects of Immunization With the Soil-Derived Bacterium Mycobacterium vaccae on Stress Coping Behaviors and Cognitive Performance in a “Two Hit” Stressor Model

Myricetin Inhibited Fear and Anxiety-Like Behaviors by HPA Axis Regulation and Activation of the BDNF-ERK Signaling Pathway in Posttraumatic Stress Disorder Rats

Effect of Short and Long Term Restraint Stress on the Histology of Liver, Kidney and Suprarenal Gland in Albino Mice during Postweaning Period

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