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Keller BN, Hajnal A, Browning KN, Arnold AC, Silberman Y. Involvement of the Dorsal Vagal Complex in Alcohol-Related Behaviors. Front Behav Neurosci 2022; 16:801825. [PMID: 35330845 PMCID: PMC8940294 DOI: 10.3389/fnbeh.2022.801825] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 01/19/2022] [Indexed: 12/20/2022] Open
Abstract
The neurobiological mechanisms that regulate the development and maintenance of alcohol use disorder (AUD) are complex and involve a wide variety of within and between systems neuroadaptations. While classic reward, preoccupation, and withdrawal neurocircuits have been heavily studied in terms of AUD, viable treatment targets from this established literature have not proven clinically effective as of yet. Therefore, examination of additional neurocircuitries not classically studied in the context of AUD may provide novel therapeutic targets. Recent studies demonstrate that various neuropeptides systems are important modulators of alcohol reward, seeking, and intake behaviors. This includes neurocircuitry within the dorsal vagal complex (DVC), which is involved in the control of the autonomic nervous system, control of intake of natural rewards like food, and acts as a relay of interoceptive sensory information via interactions of numerous gut-brain peptides and neurotransmitter systems with DVC projections to central and peripheral targets. DVC neuron subtypes produce a variety of neuropeptides and transmitters and project to target brain regions critical for reward such as the mesolimbic dopamine system as well as other limbic areas important for the negative reinforcing and aversive properties of alcohol withdrawal such as the extended amygdala. This suggests the DVC may play a role in the modulation of various aspects of AUD. This review summarizes the current literature on neurotransmitters and neuropeptides systems in the DVC (e.g., norepinephrine, glucagon-like peptide 1, neurotensin, cholecystokinin, thyrotropin-releasing hormone), and their potential relevance to alcohol-related behaviors in humans and rodent models for AUD research. A better understanding of the role of the DVC in modulating alcohol related behaviors may lead to the elucidation of novel therapeutic targets for drug development in AUD.
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Marsland P, Parrella A, Orlofsky M, Lovelock DF, Vore AS, Varlinskaya EI, Deak T. Neuroendocrine and neuroimmune responses in male and female rats: evidence for functional immaturity of the neuroimmune system during early adolescence. Eur J Neurosci 2021; 55:2311-2325. [PMID: 33458889 PMCID: PMC8287786 DOI: 10.1111/ejn.15118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/30/2020] [Accepted: 01/06/2021] [Indexed: 02/06/2023]
Abstract
Adolescence is a developmental period characterized by rapid behavioral and physiological changes, including enhanced vulnerability to stress. Recent studies using rodent models of adolescence have demonstrated age differences in neuroendocrine responses and blunted neuroimmune responding to pharmacological challenges. The present study was designed to test whether this neuroimmune insensitivity would generalize to a non-pharmacological stress challenge. Male and female adolescent (P29-33) and adult (P70-80) Sprague Dawley rats were exposed to intermittent footshock for one-, two-, or two-hours + recovery. Plasma corticosterone and progesterone levels as well as gene expression of several cytokines and c-Fos gene expression in the paraventricular nucleus of the hypothalamus (PVN), the medial amygdala (MeA), and the ventral hippocampus (vHPC) were analyzed. The results of the present study demonstrated differences in response to footshock, with these differences dependent on age, sex, and brain region of interest. Adult males and females demonstrated time-dependent increases in IL-1β and IL-1R2 in the PVN, with these changes not evident in adolescent males and substantially blunted in adolescent females. TNFα expression was decreased in all regions of interest, with adults demonstrating more suppression relative to adolescents and age differences more apparent in males than in females. IL-6 expression was affected by footshock predominantly in the vHPC of adolescent and adult males and females, with females demonstrating prolonged elevation of IL-6 gene expression. In summary, central cytokine responses to acute stressor exposure are blunted in adolescent rats, with the most pronounced immaturity evident for the brain IL-1 signaling system.
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Affiliation(s)
- Paige Marsland
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Allissa Parrella
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Maya Orlofsky
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Dennis F Lovelock
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Andrew S Vore
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Elena I Varlinskaya
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Terrence Deak
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
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Martinez-Muniz GA, Wood SK. Sex Differences in the Inflammatory Consequences of Stress: Implications for Pharmacotherapy. J Pharmacol Exp Ther 2020; 375:161-174. [PMID: 32759370 DOI: 10.1124/jpet.120.266205] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 07/28/2020] [Indexed: 12/21/2022] Open
Abstract
Women are at significantly greater risk of developing stress-related disorders such as depression. The increased risk begins during puberty and continues throughout life until menopause, suggesting a role for ovarian hormones in this increased susceptibility. Importantly, inflammation has been gaining momentum in its role in the pathogenesis of depression. Herein, clinical and preclinical studies have been reviewed to better understand how sex differences within the immune system may contribute to exaggerated risk of depression in females. First, studies that investigate the ability of psychologic stress episodes to engage the inflammatory systems both in the brain and periphery are reviewed with a special focus on sex-specific effects. Moreover, studies are discussed that identify whether imbalanced inflammatory milieu contributes to the development of depression in males versus females and whether these effects are regulated by estradiol. Importantly, we propose a locus coeruleus-norepinephrine-cytokine circuit as a conduit through which stress could increase stress susceptibly in females. Finally, the anti-inflammatory capacity of traditional and nontraditional antidepressants is investigated, with the goal of providing a better understanding of pharmacotherapeutics to enhance strategies to personalize antidepressant treatments between the sexes. The studies reviewed herein strongly support the need for further studies to elucidate whether females are especially sensitive to anti-inflammatory compounds as adjuvants to traditional therapies. SIGNIFICANCE STATEMENT: Women have hve an increased risk of developing stress-related disorders such as depression. In this review, literature from clinical and preclinical studies are integrated to define sex differences in stress-induced inflammatory responses as a potential source for the etiology of sex differences in depressive disorders. Moreover, the anti-inflammatory capacity of traditional and nontraditional antidepressants is reviewed to inform on potential pharmacotherapeutic strategies to personalize antidepressant therapy in a sex-dependent manner.
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Affiliation(s)
- Gustavo A Martinez-Muniz
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina and Dorn Veterans Administration Medical Center, Columbia, South Carolina
| | - Susan K Wood
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina and Dorn Veterans Administration Medical Center, Columbia, South Carolina
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Hueston CM, Deak T. Corticosterone and progesterone differentially regulate HPA axis and neuroimmune responses to stress in male rats. Stress 2020; 23:368-385. [PMID: 31591928 DOI: 10.1080/10253890.2019.1678025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In response to stressor exposure, expression of the inflammatory cytokine interleukin-1β (IL-1) is increased within the paraventricular nucleus of the hypothalamus (PVN). Surgical removal of the adrenal glands (ADX) potentiated stress-induced IL-1 expression, suggesting a role for adrenal-derived hormones in constraining stress-evoked increases in IL-1. While corticosterone (CORT) is a primary factor inhibiting IL-1 expression, progesterone (PROG) is also released by the adrenal glands in male rats in response to stress and also has potent anti-inflammatory properties. This series of studies first established doses of CORT and PROG that adequately recapitulate the normal stress-induced rise, and then tested for individual and combined roles of CORT and PROG in mitigating stress-induced expression of inflammatory genes. We found that CORT injection alone attenuated ADX-induced increases in IL-1 expression and normalized the HPA axis response to stress. In general, PROG replacement had little effect on changes in HPA axis responsivity or stress-induced inflammatory measures. When CORT and PROG were co-administered, a small effect on expression of the decoy receptor, IL-1R2 was observed, suggestive of an anti-inflammatory response. Overall, these results suggest that although CORT is likely to be the primary stress-related hormone responsible for constraining cytokine expression evoked by stress, CORT and PROG may exert certain combined actions that temper stress-induced neuroinflammation.LAY SUMMARYExposure to stress promoted expression of inflammation-related genes in the PVN and BNST. This inflammation was mainly suppressed by the adrenal hormone corticosterone, whereas progesterone had a smaller role in mitigating post-stress inflammation.
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Affiliation(s)
- Cara M Hueston
- Behavioral Neuroscience Program, Department of Psychology, State University of New York at Binghamton, Binghamton, NY, USA
| | - Terrence Deak
- Behavioral Neuroscience Program, Department of Psychology, State University of New York at Binghamton, Binghamton, NY, USA
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5
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Lovelock DF, Deak T. Acute stress imposed during adolescence yields heightened anxiety in Sprague Dawley rats that persists into adulthood: Sex differences and potential involvement of the Medial Amygdala. Brain Res 2019; 1723:146392. [PMID: 31446016 DOI: 10.1016/j.brainres.2019.146392] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/26/2019] [Accepted: 08/14/2019] [Indexed: 12/14/2022]
Abstract
Stressors experienced during adolescence have been demonstrated to have a long-lasting influence on affective behavior in adulthood. Notably, most studies to date have found these outcomes after chronic stress during adolescence. In the present study we tested how exposure to a single episode of acute footshock during early adolescence would modify subsequent adult anxiety- and depressive-like behaviors in male and female Sprague-Dawley rats. Adolescent rats were exposed to inescapable footshock (80 shocks, 5 s, 1.0 mA, 90 sec variable inter-trial interval (ITI)) at Post-natal day (PND) 29-30 and remained undisturbed until adulthood where they were evaluated with several behavioral assays for anxiety as well as depressive-like behavior via forced swim. In addition, gene expression changes were assessed immediately after a 30 min forced swim challenge in adulthood among several stress-related brain regions including the Central Amygdala (CeA), Medial Amygdala (MeA), ventral Hippocampus (vHPC), and Paraventricular Nucleus (PVN). Studies used real-time RT-PCR to examine the cytokines Interleukin-1β (IL-1β) and Interleukin-6 (IL-6), corticotropin-releasing hormone (CRH), the immediate early genes c-Fos, c-Jun, Egr1 and Arc, and several genes relating to corticosteroid receptor function (glucocorticoid and mineralocorticoid receptor (GR and MR, respectively), Gilz (glucocorticoid-induced leucine zipper), Sgk1 (Serum and Glucocorticoid regulated Kinase 1)). Behaviorally, males displayed signs of increased anxiety, most notably in the light-dark box, whereas females did not. No notable depressive-like behavior was observed in forced swim as a result of adolescent stress history, but adolescent footshock exacerbated the c-Fos response in the MeA produced by swim in both sexes. Forced swim led to increased IL-1β expression in the PVN regardless of adolescent stress history, whereas most HPA (hypothalamic-pituitaryadrenal) axis-related genes were largely unaffected in the vHPC. To determine the potential for β-adrenergic receptors to contribute to the male-specific anxiety-like behavior, two further studies applied a β-adrenergic agonist (isoproterenol) or antagonist (propranolol) in male rats. These studies found that propranolol administered 2 h after footshock led to a reduction in some anxiety-like behaviors as compared to controls. Overall, these findings suggest that exposure to a single, intense stress challenge imposed during adolescence may have sex-specific consequences across the lifespan and may implicate the MeA in developmental plasticity.
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Affiliation(s)
- Dennis F Lovelock
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY 13902-6000, United States.
| | - Terrence Deak
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY 13902-6000, United States.
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6
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Johnson JD, Barnard DF, Kulp AC, Mehta DM. Neuroendocrine Regulation of Brain Cytokines After Psychological Stress. J Endocr Soc 2019; 3:1302-1320. [PMID: 31259292 PMCID: PMC6595533 DOI: 10.1210/js.2019-00053] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 05/06/2019] [Indexed: 12/22/2022] Open
Abstract
There is growing evidence that stress-induced brain cytokines are important in the etiology of depression and anxiety. Here, we review how the neuroendocrine responses to psychological stressors affect the immediate and long-term regulation of inflammatory cytokines within the brain and highlight how the regulation changes across time with repeated stress exposure. In doing so, we report on the percentage of studies in the literature that observed increases in either IL-1β, TNF-α, or IL-6 within the hypothalamus, hippocampus, or prefrontal cortex after either acute or chronic stress exposure. The key takeaway is that catecholamines and glucocorticoids play critical roles in the regulation of brain cytokines after psychological stress exposure. Central catecholamines stimulate the release of IL-1β from microglia, which is a key factor in the further activation of microglia and recruitment of monocytes into the brain. Meanwhile, the acute elevation of glucocorticoids inhibits the production of brain cytokines via two mechanisms: the suppression of noradrenergic locus coeruleus neurons and inhibition of the NFκB signaling pathway. However, glucocorticoids and peripheral catecholamines facilitate inflammatory responses to future stimuli by stimulating monocytes to leave the bone marrow, downregulating inhibitory receptors on microglia, and priming inflammatory responses mediated by peripheral monocytes or macrophages. The activation of microglia and the elevation of peripheral glucocorticoid and catecholamine levels are both necessary during times of stress exposure for the development of psychopathologies.
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Affiliation(s)
- John D Johnson
- Kent State University, Biological Sciences Department, School of Biomedical Sciences, Kent, Ohio
| | - David F Barnard
- Kent State University, Biological Sciences Department, School of Biomedical Sciences, Kent, Ohio
| | - Adam C Kulp
- Kent State University, Biological Sciences Department, School of Biomedical Sciences, Kent, Ohio
| | - Devanshi M Mehta
- Kent State University, Biological Sciences Department, School of Biomedical Sciences, Kent, Ohio
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Perkins AE, Varlinskaya EI, Deak T. Impact of housing conditions on social behavior, neuroimmune markers, and oxytocin receptor expression in aged male and female Fischer 344 rats. Exp Gerontol 2019; 123:24-33. [PMID: 31100373 DOI: 10.1016/j.exger.2019.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 04/23/2019] [Accepted: 05/10/2019] [Indexed: 01/30/2023]
Abstract
Aging is associated with a substantial decline in social behavior, whereas positive social interaction can improve overall health in aged individuals. In laboratory rodents, manipulations of the social environment across the lifespan have been shown to affect social behavior. Therefore, we examined the effects of long-term (5-6 weeks) housing conditions (alone, with one adult, or with two adults) on social behavior and the expression of neuroinflammation-related genes as well as oxytocin receptor (OXTR) gene expression in brain areas associated with social behavior regulation in aged male and female Fischer (F) 344 rats. Single-housed males and females exhibited increased social investigation, relative to pair-housed rats (one aged and one adult). Triple-housed (one aged and two adults) aged males exhibited lower levels of social investigation, relative to triple-housed aged females. Aged females were more socially active that their male counterparts. Although social housing condition significantly affected social behavior in males, it had no impact on cytokine gene expression in the paraventricular nucleus of hypothalamus (PVN), bed nucleus of the stria terminalis (BNST) or medial amygdala (MeA). However, in triple-housed aged females, who exhibited social behavior comparable to their single- and pair-housed counterparts, there was a significant increase in the expression of IL-1β and IL-6 mRNA in the MeA. No changes in cytokine gene expression were observed in the PVN or BNST, indicating that the increased expression of cytokines in the MeA was not a result of a generalized increase in neuroinflammation. Single-housed males and females exhibited elevated OXTR gene expression in the BNST. Taken together, these data indicate that manipulations of the social environment in late aging significantly influenced social interactions with a novel partner and gene expression in social behavior circuits and that these effects are sex-specific.
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Affiliation(s)
- Amy E Perkins
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University-SUNY, Binghamton, NY 13902-6000, United States of America
| | - Elena I Varlinskaya
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University-SUNY, Binghamton, NY 13902-6000, United States of America
| | - Terrence Deak
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University-SUNY, Binghamton, NY 13902-6000, United States of America.
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Yasuda A, Seki T, Kametani Y, Koizumi M, Kitajima N, Oki M, Seki M, Kakuta T, Fukagawa M. Glucocorticoid Receptor Antagonist Administration Prevents Adrenal Gland Atrophy in an ACTH-Independent Cushing's Syndrome Rat Model. Int J Endocrinol 2019; 2019:8708401. [PMID: 30915117 PMCID: PMC6399522 DOI: 10.1155/2019/8708401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 01/06/2019] [Indexed: 11/17/2022] Open
Abstract
ACTH-independent Cushing's syndrome (CS) is mainly caused by cortisol-secreting adrenocortical tumours. It is well known that secondary adrenal insufficiency occurs after surgical resection of these tumours. In this regard, impaired adrenocortical function is likely induced by atrophy of the residual adrenal tissue as a result of chronic suppression by the low ACTH levels of the hypercortisolism state. Therefore, we considered the prevention of adrenal atrophy as a method for preventing postoperative adrenal insufficiency. On the basis of these findings, we hypothesized that the use of a glucocorticoid receptor (GR) antagonist before surgery in ACTH-independent CS would rapidly activate the hypothalamic-pituitary-adrenal (HPA) axis and residual adrenal function. We thus examined adrenal function in a dexamethasone- (DEX-) induced CS rat model with or without mifepristone (MIF). In this study, MIF-treated rats had elevated plasma ACTH levels and increased adrenal weights. In addition, we confirmed that there were fewer atrophic changes, as measured by the pathological findings and mRNA expression levels of corticosterone synthase CYP11B1 in the adrenal glands, in MIF-treated rats. These results indicate that MIF treatment prevents the suppression of the HPA axis and the atrophy of the residual adrenal tissue. Therefore, our study suggests that preoperative GR antagonist administration may improve residual adrenal function and prevent postoperative adrenal insufficiency in ACTH-independent CS.
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Affiliation(s)
- Atsushi Yasuda
- Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Toshiro Seki
- Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Yoshie Kametani
- Department of Molecular Life Science, Division of Basic Medical Science, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Masahiro Koizumi
- Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Natsumi Kitajima
- Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Masayuki Oki
- Division of General Internal Medicine, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Masami Seki
- Seirei Numazu Hospital, Shizuoka 410-8555, Japan
| | - Takatoshi Kakuta
- Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
| | - Masafumi Fukagawa
- Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa 259-1193, Japan
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Finnell JE, Wood SK. Putative Inflammatory Sensitive Mechanisms Underlying Risk or Resilience to Social Stress. Front Behav Neurosci 2018; 12:240. [PMID: 30416436 PMCID: PMC6212591 DOI: 10.3389/fnbeh.2018.00240] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 09/25/2018] [Indexed: 12/30/2022] Open
Abstract
It has been well recognized that exposure to stress can lead to the onset of psychosocial disorders such as depression. While there are a number of antidepressant therapies currently available and despite producing immediate neurochemical alterations, they require weeks of continuous use in order to exhibit antidepressant efficacy. Moreover, up to 30% of patients do not respond to typical antidepressants, suggesting that our understanding of the pathophysiology underlying stress-induced depression is still limited. In recent years inflammation has become a major focus in the study of depression as several clinical and preclinical studies have demonstrated that peripheral and central inflammatory mediators, including interleukin (IL)-1β, are elevated in depressed patients. Moreover, it has been suggested that inflammation and particularly neuroinflammation may be a direct and immediate link in the emergence of stress-induced depression due to the broad neural and glial effects that are elicited by proinflammatory cytokines. Importantly, individual differences in inflammatory reactivity may further explain why certain individuals exhibit differing susceptibility to the consequences of stress. In this review article, we discuss sources of individual differences such as age, sex and coping mechanisms that are likely sources of distinct changes in stress-induced neuroimmune factors and highlight putative sources of exaggerated neuroinflammation in susceptible individuals. Furthermore, we review the current literature of specific neural and glial mechanisms that are regulated by stress and inflammation including mitochondrial function, oxidative stress and mechanisms of glutamate excitotoxicity. Taken together, the impetus for this review is to move towards a better understanding of mechanisms regulated by inflammatory cytokines and chemokines that are capable of contributing to the emergence of depressive-like behaviors in susceptible individuals.
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Affiliation(s)
- Julie E Finnell
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Susan K Wood
- Department of Pharmacology, Physiology, and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States.,WJB Dorn Veterans Administration Medical Center, Columbia, SC, United States
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Neuroendocrine and neuroimmune adaptation to Chronic Escalating Distress (CED): A novel model of chronic stress. Neurobiol Stress 2018; 9:74-83. [PMID: 30450375 PMCID: PMC6234279 DOI: 10.1016/j.ynstr.2018.08.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 08/04/2018] [Accepted: 08/18/2018] [Indexed: 11/21/2022] Open
Abstract
Acute and chronic stress challenges have a profound influence on the development and expression of subsequent affective disorders, alcohol use disorders, and natural aging processes. These experiments examined adaptation in neuroimmune and neuroendocrine responses that occurred as a result of exposure to a novel model of chronic stress, termed chronic escalating distress (CED). This model involves exposure to highly predictable daily stress challenges involving a systematic escalation in both the intensity and length of daily stress challenges, and has recently been shown to profoundly alter alcohol sensitivity. Male Sprague-Dawley rats were exposed to an 11 day procedure where days 1-5 consisted of 60 min of restraint, days 6-10 consisted of 60 min of restraint immediately followed by 30 min of forced swim, and on day 11 subjects were exposed to a 2 h session of intermittent footshock. Experiment 1 examined adaptation in the corticosterone (CORT) response at key points in the 11 day procedure, and found that the escalation in stressors disrupted habituation to restraint, whereas the CORT response to daily forced swim exposure increased across days. Experiment 2 investigated the impact of this stress paradigm on the expression of several cytokine (IL-1β, IL-6, TNF-α) and cellular activation marker (c-Fos, CD14, CD200R) genes in key brain regions (PVN, HPC, & PFC) known to be influenced by stress. Interestingly, a history of CED had no effect on footshock-induced neuroimmune changes (increased IL-1 in the PVN; increased IL-6 in the HPC and PFC). In addition, acute footshock and CED produced similar c-fos induction within the PVN whereas CED led to enhanced c-fos induction in both the HPC and PFC. These findings support recent work indicating that neuroimmune responses to acute stress challenges persisted in rats with a recent history of repeated stress exposure, and that these effects occurred contemporaneously with ongoing changes in HPA axis reactivity. Overall, this CED model may serve as a highly tractable model for studying adaptation to chronic stress, and may have implications for understanding stress-induced alterations in alcohol sensitivity and natural aging processes.
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11
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Herman JP. Regulation of Hypothalamo-Pituitary-Adrenocortical Responses to Stressors by the Nucleus of the Solitary Tract/Dorsal Vagal Complex. Cell Mol Neurobiol 2017; 38:25-35. [PMID: 28895001 DOI: 10.1007/s10571-017-0543-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 08/24/2017] [Indexed: 01/04/2023]
Abstract
Hindbrain neurons in the nucleus of the solitary tract (NTS) are critical for regulation of hypothalamo-pituitary-adrenocortical (HPA) responses to stress. It is well known that noradrenergic (as well as adrenergic) neurons in the NTS send direct projections to hypophysiotropic corticotropin-releasing hormone (CRH) neurons and control activation of HPA axis responses to acute systemic (but not psychogenic) stressors. Norepinephrine (NE) signaling via alpha1 receptors is primarily excitatory, working either directly on CRH neurons or through presynaptic activation of glutamate release. However, there is also evidence for NE inhibition of CRH neurons (possibly via beta receptors), an effect that may occur at higher levels of stimulation, suggesting that NE effects on the HPA axis may be context-dependent. Lesions of ascending NE inputs to the paraventricular nucleus attenuate stress-induced ACTH but not corticosterone release after chronic stress, indicating reduction in central HPA drive and increased adrenal sensitivity. Non-catecholaminergic NTS glucagon-like peptide 1/glutamate neurons play a broader role in stress regulation, being important in HPA activation to both systemic and psychogenic stressors as well as HPA axis sensitization under conditions of chronic stress. Overall, the data highlight the importance of the NTS as a key regulatory node for coordination of acute and chronic stress.
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Affiliation(s)
- James P Herman
- Stress Neurobiology Laboratory, Department of Psychiatry and Behavioral Neuroscience, UC Neurobiology Research Center, University of Cincinnati, 2170 East Galbraith Road, Cincinnati, OH, 45237-0506, USA.
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12
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Deak T, Kudinova A, Lovelock DF, Gibb BE, Hennessy MB. A multispecies approach for understanding neuroimmune mechanisms of stress. DIALOGUES IN CLINICAL NEUROSCIENCE 2017. [PMID: 28566946 PMCID: PMC5442363 DOI: 10.31887/dcns.2017.19.1/tdeak] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The relationship between stress challenges and adverse health outcomes, particularly for the development of affective disorders, is now well established. The highly conserved neuroimmune mechanisms through which responses to stressors are transcribed into effects on males and females have recently garnered much attention from researchers and clinicians alike. The use of animal models, from mice to guinea pigs to primates, has greatly increased our understanding of these mechanisms on the molecular, cellular, and behavioral levels, and research in humans has identified particular brain regions and connections of interest, as well as associations between stress-induced inflammation and psychiatric disorders. This review brings together findings from multiple species in order to better understand how the mechanisms of the neuroimmune response to stress contribute to stress-related psychopathologies, such as major depressive disorder, schizophrenia, and bipolar disorder.
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Affiliation(s)
- Terrence Deak
- Center for Affective Science and Department of Psychology, Binghamton University-State University of New York (SUNY), Binghamton, New York, USA
| | - Anastacia Kudinova
- Center for Affective Science and Department of Psychology, Binghamton University-State University of New York (SUNY), Binghamton, New York, USA
| | - Dennis F Lovelock
- Center for Affective Science and Department of Psychology, Binghamton University-State University of New York (SUNY), Binghamton, New York, USA
| | - Brandon E Gibb
- Center for Affective Science and Department of Psychology, Binghamton University-State University of New York (SUNY), Binghamton, New York, USA
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Lovelock DF, Deak T. Repeated exposure to two stressors in sequence demonstrates that corticosterone and paraventricular nucleus of the hypothalamus interleukin-1β responses habituate independently. J Neuroendocrinol 2017; 29:10.1111/jne.12514. [PMID: 28803453 PMCID: PMC5617797 DOI: 10.1111/jne.12514] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 08/07/2017] [Accepted: 08/08/2017] [Indexed: 01/09/2023]
Abstract
A wide range of stress-related pathologies such as post-traumatic stress disorder are considered to arise from aberrant or maladaptive forms of stress adaptation. The hypothalamic-pituitary-adrenal (HPA) axis readily adapts to repeated stressor exposure, yet little is known about adaptation in neuroimmune responses to repeated or sequential stress challenges. In Experiment 1, rats were exposed to 10 days of restraint alone (60 minutes daily), forced swim alone (30 minutes daily) or daily sequential exposure to restraint (60 minutes) followed immediately by forced swim (30 minutes), termed sequential stress exposure. Habituation of the corticosterone (CORT) response occurred to restraint by 5 days and swim at 10 days, whereas rats exposed to sequential stress exposure failed to display habituation to the combined challenge. Experiment 2 compared 1 or 5 days of forced swim with sequential stress exposure and examined how each affected expression of several neuroimmune and cellular activation genes in the paraventricular nucleus of the hypothalamus (PVN), prefrontal cortex (PFC) and hippocampus (HPC). Sequential exposure to restraint and swim increased interleukin (IL)-1β in the PVN, an effect that was attenuated after 5 days. Sequential stress exposure also elicited IL-6 and tumour necrosis factor-α responses in the HPC and PFC, respectively, which did not habituate after 5 days. Experiment 3 tested whether prior habituation to restraint (5 days) would alter the IL-1β response evoked by swim exposure imposed immediately after the sixth day of restraint. Surprisingly, a history of repeated exposure to restraint attenuated the PVN IL-1β response after swim in comparison to acutely-exposed subjects despite an equivalent CORT response. Overall, these findings suggest that habituation of neuroimmune responses to stress proceeds: (i) independent of HPA axis habituation; (ii) likely requires more daily sessions of stress to develop; and (iii) IL-1β displays a greater tendency to habituate after repeated stress challenges compared to other stress-reactive cytokines.
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Affiliation(s)
- Dennis F. Lovelock
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University—SUNY, Binghamton NY 13902-6000
| | - Terrence Deak
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University—SUNY, Binghamton NY 13902-6000
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14
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Gano A, Doremus-Fitzwater TL, Deak T. Sustained alterations in neuroimmune gene expression after daily, but not intermittent, alcohol exposure. Brain Res 2016; 1646:62-72. [PMID: 27208497 DOI: 10.1016/j.brainres.2016.05.027] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/28/2016] [Accepted: 05/13/2016] [Indexed: 12/15/2022]
Abstract
Acute ethanol intoxication is associated with Rapid Alterations in Neuroimmune Gene Expression (RANGE), including increased Interleukin (IL)-6 and Nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα), and suppressed IL-1β and Tumor necrosis factor (TNF) α, yet little is known about adaptations in cytokines across the first few ethanol exposures. Thus, the present studies examined central cytokines during intoxication (3h post-ethanol) following 2, 4 or 6 intragastric ethanol challenges (4g/kg) delivered either daily or every-other-day (EOD). Subsequent analyses of blood ethanol concentrations (BECs) and corticosterone were performed to determine whether the schedule of ethanol delivery would alter the pharmacokinetics of, or general sensitivity to, subacute ethanol exposure. As expected, ethanol led to robust increases in IL-6 and IκBα gene expression in hippocampus, amygdala and bed nucleus of the stria terminalis (BNST), whereas IL-1β and TNFα were suppressed, thereby replicating our prior work. Ethanol-dependent increases in IL-6 and IκBα remained significant in all structures - even after 6 days of ethanol. When these doses were administered EOD, modest IL-6 increases in BNST were observed, with TNFα and IL-1β suppressed exclusively in the hippocampus. Analysis of BECs revealed a small but significant reduction in ethanol after 4 EOD exposures - an effect which was not observed when ethanol was delivered after 6 daily intubations. These findings suggest that ethanol-induced RANGE effects are not simply a function of ethanol load per se, and underscore the critical role that ethanol dosing interval plays in determining the neuroimmune consequences of alcohol.
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Affiliation(s)
- Anny Gano
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY 13902-6000, United States
| | - Tamara L Doremus-Fitzwater
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY 13902-6000, United States
| | - Terrence Deak
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY 13902-6000, United States.
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15
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Rea K, Dinan TG, Cryan JF. The microbiome: A key regulator of stress and neuroinflammation. Neurobiol Stress 2016; 4:23-33. [PMID: 27981187 PMCID: PMC5146205 DOI: 10.1016/j.ynstr.2016.03.001] [Citation(s) in RCA: 303] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/03/2016] [Accepted: 03/03/2016] [Indexed: 02/06/2023] Open
Abstract
There is a growing emphasis on the relationship between the complexity and diversity of the microorganisms that inhabit our gut (human gastrointestinal microbiota) and health/disease, including brain health and disorders of the central nervous system. The microbiota-gut-brain axis is a dynamic matrix of tissues and organs including the brain, glands, gut, immune cells and gastrointestinal microbiota that communicate in a complex multidirectional manner to maintain homeostasis. Changes in this environment can lead to a broad spectrum of physiological and behavioural effects including hypothalamic-pituitary-adrenal (HPA) axis activation, and altered activity of neurotransmitter systems and immune function. While an appropriate, co-ordinated physiological response, such as an immune or stress response are necessary for survival, a dysfunctional response can be detrimental to the host contributing to the development of a number of CNS disorders. In this review, the involvement of the gastrointestinal microbiota in stress-mediated and immune-mediated modulation of neuroendocrine, immune and neurotransmitter systems and the consequential behaviour is considered. We also focus on the mechanisms by which commensal gut microbiota can regulate neuroinflammation and further aim to exploit our understanding of their role in stress-related disorders as a consequence of neuroinflammatory processes.
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Affiliation(s)
- Kieran Rea
- APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Timothy G Dinan
- APC Microbiome Institute, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland
| | - John F Cryan
- APC Microbiome Institute, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
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16
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Doremus-Fitzwater TL, Buck HM, Bordner K, Richey L, Jones ME, Deak T. Intoxication- and withdrawal-dependent expression of central and peripheral cytokines following initial ethanol exposure. Alcohol Clin Exp Res 2015; 38:2186-98. [PMID: 25156612 DOI: 10.1111/acer.12481] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 04/21/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND Evidence has emerged demonstrating that ethanol (EtOH) influences cytokine expression within the central nervous system, although most studies have examined long-term exposure. Thus, the cytokine response to an acute EtOH challenge was investigated, in order to characterize profiles of cytokine changes following acute exposure. METHODS Rats pups were injected intraperitoneally (i.p.) with 2-g/kg EtOH, and IL-1 mRNA and protein were assessed 0, 60, 120, 180, and 240 minutes post injection (Experiment 1). In Experiments 2 to 5, the expression of several cytokines was examined in adult male rats during acute intoxication (3 hours after 4-g/kg EtOH), as well as withdrawal (18 hours post injection), after i.p. or intragastric (i.g.) EtOH administration. RESULTS Early in ontogeny, acute EtOH significantly decreased brain IL-1 mRNA and protein. Subsequently, when adult rats were examined, significant and temporally dynamic alterations in central and peripheral cytokines were observed following acute i.p. EtOH exposure (4 g/kg). Although cytokine- and region-dependent central IL-6 expression was generally increased and tumor necrosis factor alpha decreased during intoxication, IL-1 expression exhibited increases during withdrawal. In the periphery, acute i.p. EtOH elevated expression of all cytokines, with the response growing in magnitude as the time post injection increased. Following acute i.g. EtOH (4 g/kg), intoxication-related increases in IL-6 expression were again observed in the paraventricular nucleus of the hypothalamus (PVN), although to a lesser extent. Long-term, voluntary, intermittent EtOH consumption resulted in tolerance to the effects of an i.g. EtOH challenge (4 g/kg) on PVN IL-6 expression, whereas these same elevations in IL-6 expression were still seen in the amygdala in rats with a history of moderate EtOH intake. Treatment with minocycline did not significantly attenuate i.p. or i.g. EtOH-induced changes in central cytokine expression. CONCLUSIONS Together, these studies provide a foundation for understanding fluctuations in central and peripheral cytokines following acute EtOH as potential contributors to the constellation of neural and behavioral alterations observed during EtOH intoxication and withdrawal.
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Affiliation(s)
- Tamara L Doremus-Fitzwater
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University-State University of New York, Binghamton, New York
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17
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Deak T, Quinn M, Cidlowski JA, Victoria NC, Murphy AZ, Sheridan JF. Neuroimmune mechanisms of stress: sex differences, developmental plasticity, and implications for pharmacotherapy of stress-related disease. Stress 2015; 18:367-80. [PMID: 26176590 PMCID: PMC4813310 DOI: 10.3109/10253890.2015.1053451] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The last decade has witnessed profound growth in studies examining the role of fundamental neuroimmune processes as key mechanisms that might form a natural bridge between normal physiology and pathological outcomes. Rooted in core concepts from psychoneuroimmunology, this review utilizes a succinct, exemplar-driven approach of several model systems that contribute significantly to our knowledge of the mechanisms by which neuroimmune processes interact with stress physiology. Specifically, we review recent evidence showing that (i) stress challenges produce time-dependent and stressor-specific patterns of cytokine/chemokine expression in the CNS; (ii) inflammation-related genes exhibit unique expression profiles in males and females depending upon individual, cooperative or antagonistic interactions between steroid hormone receptors (estrogen and glucocorticoid receptors); (iii) adverse social experiences incurred through repeated social defeat engage a dynamic process of immune cell migration from the bone marrow to brain and prime neuroimmune function and (iv) early developmental exposure to an inflammatory stimulus (carageenin injection into the hindpaw) has a lasting influence on stress reactivity across the lifespan. As such, the present review provides a theoretical framework for understanding the role that neuroimmune mechanisms might play in stress plasticity and pathological outcomes, while at the same time pointing toward features of the individual (sex, developmental experience, stress history) that might ultimately be used for the development of personalized strategies for therapeutic intervention in stress-related pathologies.
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Affiliation(s)
- Terrence Deak
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University-SUNY, Binghamton, NY 13902-6000
- Address correspondence to: Terrence Deak, Ph.D., , Phone: 607-777-5918
| | - Matt Quinn
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - John A. Cidlowski
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709
| | - Nicole C. Victoria
- Neuroscience Institute, Georgia State University, Petit Science Center, PO Box 5030, Atlanta, GA 30302-5030
| | - Anne Z. Murphy
- Neuroscience Institute, Georgia State University, Petit Science Center, PO Box 5030, Atlanta, GA 30302-5030
| | - John F. Sheridan
- The Ohio State University College of Dentistry and Institute for Behavioral Medicine Research, The Ohio State University Wexner Medical Center, Columbus, OH 43210
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18
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Uchoa ET, Aguilera G, Herman JP, Fiedler JL, Deak T, Cordeiro de Sousa MB. Novel aspects of glucocorticoid actions. J Neuroendocrinol 2014; 26:557-72. [PMID: 24724595 PMCID: PMC4161987 DOI: 10.1111/jne.12157] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 04/06/2014] [Accepted: 04/08/2014] [Indexed: 12/20/2022]
Abstract
Normal hypothalamic-pituitary-adrenal (HPA) axis activity leading to the rhythmic and episodic release of adrenal glucocorticoids (GCs) is essential for body homeostasis and survival during stress. Acting through specific intracellular receptors in the brain and periphery, GCs regulate behaviour, as well as metabolic, cardiovascular, immune and neuroendocrine activities. By contrast to chronic elevated levels, circadian and acute stress-induced increases in GCs are necessary for hippocampal neuronal survival and memory acquisition and consolidation, as a result of the inhibition of apoptosis, the facilitation of glutamatergic neurotransmission and the formation of excitatory synapses, and the induction of immediate early genes and dendritic spine formation. In addition to metabolic actions leading to increased energy availability, GCs have profound effects on feeding behaviour, mainly via the modulation of orexigenic and anorixegenic neuropeptides. Evidence is also emerging that, in addition to the recognised immune suppressive actions of GCs by counteracting adrenergic pro-inflammatory actions, circadian elevations have priming effects in the immune system, potentiating acute defensive responses. In addition, negative-feedback by GCs involves multiple mechanisms leading to limited HPA axis activation and prevention of the deleterious effects of excessive GC production. Adequate GC secretion to meet body demands is tightly regulated by a complex neural circuitry controlling hypothalamic corticotrophin-releasing hormone (CRH) and vasopressin secretion, which are the main regulators of pituitary adrenocorticotrophic hormone (ACTH). Rapid feedback mechanisms, likely involving nongenomic actions of GCs, mediate the immediate inhibition of hypothalamic CRH and ACTH secretion, whereas intermediate and delayed mechanisms mediated by genomic actions involve the modulation of limbic circuitry and peripheral metabolic messengers. Consistent with their key adaptive roles, HPA axis components are evolutionarily conserved, being present in the earliest vertebrates. An understanding of these basic mechanisms may lead to novel approaches for the development of diagnostic and therapeutic tools for disorders related to stress and alterations of GC secretion.
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Affiliation(s)
- Ernane Torres Uchoa
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Greti Aguilera
- Section on Endocrine Physiology, National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - James P. Herman
- Department of Psychiatry and Behavioural Neuroscience, University of Cincinnati, Metabolic Diseases Institute, Cincinnati, OH, USA
| | - Jenny L. Fiedler
- Department of Biochemistry and Molecular Biology, Faculty of Chemical and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Terrence Deak
- Department of Psychology, Binghamton University, Binghamton, NY, USA
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19
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The impact of the P2X7 receptor antagonist A-804598 on neuroimmune and behavioral consequences of stress. Behav Pharmacol 2014; 25:582-98. [DOI: 10.1097/fbp.0000000000000072] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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20
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Hueston CM, Deak T. The inflamed axis: the interaction between stress, hormones, and the expression of inflammatory-related genes within key structures comprising the hypothalamic-pituitary-adrenal axis. Physiol Behav 2013; 124:77-91. [PMID: 24184413 DOI: 10.1016/j.physbeh.2013.10.035] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 10/23/2013] [Indexed: 12/13/2022]
Abstract
Acute stress increases the expression of cytokines and other inflammatory-related factors in the CNS, plasma, and endocrine glands, and activation of inflammatory signaling pathways within the hypothalamic-pituitary-adrenal (HPA) axis may play a key role in later stress sensitization. In addition to providing a summary of stress effects on neuroimmune changes within the CNS, we present a series of experiments that characterize stress effects on members of the interleukin-1β (IL-1) super-family and other inflammatory-related genes in key structures comprising the HPA axis (PVN, pituitary and adrenal glands), followed by a series of experiments examining the impact of exogenous hormone administration (CRH and ACTH) and dexamethasone on the expression of inflammatory-related genes in adult male Sprague-Dawley rats. The results demonstrated robust, time-dependent, and asynchronous expression patterns for IL-1 and IL-1R2 in the PVN, with substantial increases in IL-6 and COX-2 in the adrenal glands emerging as key findings. The effects of exogenous CRH and ACTH were predominantly isolated within the adrenals. Finally, pretreatment with dexamethasone severely blunted neuroimmune changes in the adrenal glands, but not in the PVN. These findings provide novel insight into the relationship between stress, the expression of inflammatory signaling factors within key structures comprising the HPA axis, and their interaction with HPA hormones, and provide a foundation for better understanding the role of cytokines as modulators of hypothalamic, pituitary and adrenal sensitivity.
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Affiliation(s)
- Cara M Hueston
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY 13902-6000, United States
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