scholarly journals Effects of social defeat stress and fluoxetine treatment on neurogenesis and behaviour in mice that lack zinc transporter 3 (ZnT3) and vesicular zinc

2019 ◽  
Author(s):  
Brendan B. McAllister ◽  
Angela Pochakom ◽  
Selena Fu ◽  
Richard H. Dyck
Keyword(s):  
Knockout Mice ◽  
Selective Serotonin Reuptake Inhibitors ◽  
Social Defeat ◽  
Zinc Transporter ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Social Avoidance ◽  
Wild Type ◽  
Social Defeat Stress ◽  
Fluoxetine Treatment

ABSTRACTDepression is a leading cause of disability worldwide, in part because the available treatments are inadequate and do not work for many people. The neurobiology of depression, and the mechanism of action of common antidepressant drugs such as selective serotonin reuptake inhibitors (SSRIs), is not well understood. One mechanism thought to underlie the effects of these drugs is upregulation of adult hippocampal neurogenesis. Evidence indicates that vesicular zinc is required for modulation of adult hippocampal neurogenesis, at least under some circumstances. Vesicular zinc refers to zinc that is stored in the synaptic vesicles of certain neurons, including in the hippocampus, and released in response to neuronal activity. It can be eliminated from the brain by deletion of zinc transporter 3 (ZnT3), as is the case in ZnT3 knockout mice. Here, we examined the effects of repeated social defeat stress and subsequent chronic treatment with the SSRI fluoxetine on behaviour and neurogenesis in ZnT3 knockout mice. We hypothesized that fluoxetine treatment would increase neurogenesis and reverse stress-induced behavioural symptoms in wild type, but not ZnT3 knockout, mice. As anticipated, stress induced persistent depression-like effects, including social avoidance and anxiety-like behaviour. Fluoxetine decreased social avoidance, though the effect was not specific to the stressed mice, but did not affect anxiety-like behaviour. Surprisingly, stress increased the survival of neurons born 1 day after the last episode of defeat stress. Fluoxetine treatment also increased cell survival, particularly in wild type mice, though it did not affect proliferation. Our results did not support our hypothesis that vesicular zinc is required for the behavioural benefits of fluoxetine treatment. As to whether vesicular zinc is required for the neurogenic effects of fluoxetine, our results were inconclusive, warranting further investigation into the role of vesicular zinc in adult hippocampal neurogenesis.

scholarly journals Hop Bitter Acids Increase Hippocampal Dopaminergic Activity in a Mouse Model of Social Defeat Stress

2020 ◽  
Vol 21 (24) ◽  
pp. 9612
Author(s):  
Yasuhisa Ano ◽  
Shiho Kitaoka ◽  
Rena Ohya ◽  
Keiji Kondo ◽  
Tomoyuki Furuyashiki
Keyword(s):  
Mouse Model ◽  
Chronic Administration ◽  
Social Defeat ◽  
Underlying Mechanism ◽  
Mental Illnesses ◽  
Social Avoidance ◽  
Social Defeat Stress ◽  
Dopaminergic Activity ◽  
Healthy Older Adults ◽  
Bitter Acids

As daily lifestyle is closely associated with mental illnesses, diet-based preventive approaches are receiving attention. Supplementation with hop bitter acids such as iso-α-acids (IAA) and mature hop bitter acids (MHBA) improves mood states in healthy older adults. However, the underlying mechanism remains unknown. Since acute oral consumption with IAA increases dopamine levels in hippocampus and improves memory impairment via vagal nerve activation, here we investigated the effects of chronic administration of hop bitter acids on the dopaminergic activity associated with emotional disturbance in a mouse model of repeated social defeat stress (R-SDS). Chronic administration of IAA and MHBA significantly increased dopaminergic activity based on the dopamine metabolite to dopamine ratio in the hippocampus and medial prefrontal cortex following R-SDS. Hippocampal dopaminergic activity was inversely correlated with the level of R-SDS-induced social avoidance with or without IAA administration. Therefore, chronic treatment with hop bitter acids enhances stress resilience-related hippocampal dopaminergic activity.

Metabolic Regulation of Hippocampal Neuronal Development and Its Inhibition After Irradiation

2021 ◽  
Vol 80 (5) ◽  
pp. 467-475
Author(s):  
Yu-Qing Li ◽  
C Shun Wong
Keyword(s):  
Cell Fate ◽  
Metabolic Regulation ◽  
Energy Homeostasis ◽  
Neuronal Development ◽  
Adenosine Monophosphate ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Wild Type ◽  
Newborn Neuron ◽  
Negative Effect

Abstract 5′-Adenosine monophosphate-activated protein kinase (AMPK), a key regulator of cellular energy homeostasis, plays a role in cell fate determination. Whether AMPK regulates hippocampal neuronal development remains unclear. Hippocampal neurogenesis is abrogated after DNA damage. Here, we asked whether AMPK regulates adult hippocampal neurogenesis and its inhibition following irradiation. Adult Cre-lox mice deficient in AMPK in brain, and wild-type mice were used in a birth-dating study using bromodeoxyuridine to evaluate hippocampal neurogenesis. There was no evidence of AMPK or phospho-AMPK immunoreactivity in hippocampus. Increase in p-AMPK but not AMPK expression was observed in granule neurons and subgranular neuroprogenitor cells (NPCs) in the dentate gyrus within 24 hours and persisted up to 9 weeks after irradiation. AMPK deficiency in Cre-lox mice did not alter neuroblast and newborn neuron numbers but resulted in decreased newborn and proliferating NPCs. Inhibition of neurogenesis was observed after irradiation regardless of genotypes. In Cre-lox mice, there was further loss of newborn early NPCs and neuroblasts but not newborn neurons after irradiation compared with wild-type mice. These results are consistent with differential negative effect of AMPK on hippocampal neuronal development and its inhibition after irradiation.

Ankyrin-G heterozygous conditional knockout mice display increased sensitivity to social defeat stress

2021 ◽  
Author(s):  
Zachary A. Cordner ◽  
Seva G. Khambadkone ◽  
Shanshan Zhu ◽  
Justin Bai ◽  
Rasadokht Forati ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Social Defeat ◽  
Conditional Knockout ◽  
Social Defeat Stress ◽  
Conditional Knockout Mice ◽  
Ankyrin G ◽  
Increased Sensitivity

scholarly journals Ingestion of probiotic (Lactobacillus helveticus and Bifidobacterium longum) alters intestinal microbial structure and behavioral expression following social defeat stress

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Katherine A. Partrick ◽  
Anna M. Rosenhauer ◽  
Jérémie Auger ◽  
Amanda R. Arnold ◽  
Nicole M. Ronczkowski ◽  
...  
Keyword(s):  
Social Stress ◽  
Bifidobacterium Longum ◽  
Social Defeat ◽  
Lactobacillus Helveticus ◽  
Rrna Gene ◽  
Social Avoidance ◽  
Social Defeat Stress ◽  
Microbial Structure ◽  
Microbial Composition ◽  
Anti Inflammatory

AbstractSocial stress exacerbates anxious and depressive behaviors in humans. Similarly, anxiety- and depressive-like behaviors are triggered by social stress in a variety of non-human animals. Here, we tested whether oral administration of the putative anxiolytic probiotic strains Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 reduces the striking increase in anxiety-like behavior and changes in gut microbiota observed following social defeat stress in Syrian hamsters. We administered the probiotic at two different doses for 21 days, and 16S rRNA gene amplicon sequencing revealed a shift in microbial structure following probiotic administration at both doses, independently of stress. Probiotic administration at either dose increased anti-inflammatory cytokines IL-4, IL-5, and IL-10 compared to placebo. Surprisingly, probiotic administration at the low dose, equivalent to the one used in humans, significantly increased social avoidance and decreased social interaction. This behavioral change was associated with a reduction in microbial richness in this group. Together, these results demonstrate that probiotic administration alters gut microbial composition and may promote an anti-inflammatory profile but that these changes may not promote reductions in behavioral responses to social stress.

scholarly journals Elimination of Vesicular Zinc Alters the Behavioural and Neuroanatomical Effects of Social Defeat Stress in Mice

2018 ◽  
Author(s):  
Brendan B. McAllister ◽  
David K. Wright ◽  
Ryan C. Wortman ◽  
Sandy R. Shultz ◽  
Richard H. Dyck
Keyword(s):  
Corpus Callosum ◽  
Chronic Stress ◽  
Social Defeat ◽  
Volumetric Analysis ◽  
Hippocampal Neurogenesis ◽  
Wild Type ◽  
Enhanced Sensitivity ◽  
Y Maze ◽  
Genetic Deletion ◽  
Stress Susceptibility

ABSTRACTChronic stress can have deleterious effects on mental health, increasing the risk of developing depression or anxiety. But not all individuals are equally affected by stress; some are susceptible while others are more resilient. Understanding the mechanisms that lead to these differing outcomes has been a focus of considerable research. One unexplored mechanism is vesicular zinc – zinc that is released by neurons as a neuromodulator. We examined how chronic stress, induced by repeated social defeat, affects mice that lack vesicular zinc due to genetic deletion of zinc transporter 3 (ZnT3). These mice, unlike wild type mice, did not become socially avoidant of a novel conspecific, suggesting resilience to stress. However, they showed enhanced sensitivity to the potentiating effect of stress on cued fear memory. Thus, the contribution of vesicular zinc to stress susceptibility is not straightforward. Stress also increased anxiety-like behaviour but produced no deficits in a spatial Y-maze test. We found no evidence that microglial activation or hippocampal neurogenesis accounted for the differences in behavioural outcome. Volumetric analysis revealed that ZnT3 KO mice have larger corpus callosum and parietal cortex volumes, and that corpus callosum volume was decreased by stress in ZnT3 KO, but not wild type, mice.

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