Physiology and Neurobiology of Stress and Adaptation: Central Role of the Brain

2007 ◽  
Vol 87 (3) ◽  
pp. 873-904 ◽  
Author(s):  
Bruce S. McEwen
Keyword(s):  
Chronic Stress ◽  
Brain Region ◽  
Behavioral Interventions ◽  
Allostatic Load ◽  
Acute Stress ◽  
Stress Hormones ◽  
The Body ◽  
Pharmaceutical Therapy ◽  
Short Run ◽  
The Brain

The brain is the key organ of the response to stress because it determines what is threatening and, therefore, potentially stressful, as well as the physiological and behavioral responses which can be either adaptive or damaging. Stress involves two-way communication between the brain and the cardiovascular, immune, and other systems via neural and endocrine mechanisms. Beyond the “flight-or-fight” response to acute stress, there are events in daily life that produce a type of chronic stress and lead over time to wear and tear on the body (“allostatic load”). Yet, hormones associated with stress protect the body in the short-run and promote adaptation (“allostasis”). The brain is a target of stress, and the hippocampus was the first brain region, besides the hypothalamus, to be recognized as a target of glucocorticoids. Stress and stress hormones produce both adaptive and maladaptive effects on this brain region throughout the life course. Early life events influence life-long patterns of emotionality and stress responsiveness and alter the rate of brain and body aging. The hippocampus, amygdala, and prefrontal cortex undergo stress-induced structural remodeling, which alters behavioral and physiological responses. As an adjunct to pharmaceutical therapy, social and behavioral interventions such as regular physical activity and social support reduce the chronic stress burden and benefit brain and body health and resilience.

Environments, Past and Present

2020 ◽  
Author(s):  
Angela Duckworth ◽  
Keyword(s):  
Allostatic Load ◽  
Acute Stress ◽  
The Body ◽  
Physiological Changes ◽  
Long Term Effects ◽  
Flight Response ◽  
Fight Or Flight Response ◽  
The Brain ◽  
Fight Or Flight

For more than a century, scientists have known that acute stress activates the fight-or-flight response. When your life is on the line, your body reacts instantly: your heart races, your breath quickens, and a cascade of hormones sets off physiological changes that collectively improve your odds of survival. More recently, scientists have come to understand that the fight-or-flight response takes a toll on the brain and the body—particularly when stress is chronic rather than acute. Systems designed to handle transient threats also react to stress that occurs again and again, for weeks, months, or years. It turns out that poverty, abuse, and other forms of adversity repeatedly activate the fight-or-flight response, leading to long-term effects on the immune system and brain, which in turn increase the risk for an array of illnesses, including asthma, diabetes, arthritis, depression, and cardiovascular disease. Pioneering neuroscientist Bruce McEwen called this burden of chronic stress “allostatic load.”

Basic mechanisms of, and treatment targets for, stress-related disorders

2020 ◽  
pp. 829-839
Author(s):  
Bruce S. McEwen
Keyword(s):  
Early Life ◽  
Allostatic Load ◽  
Life Experiences ◽  
The Body ◽  
The Social ◽  
Wear And Tear ◽  
Short Run ◽  
Social And Physical Environment ◽  
The Impact ◽  
The Brain

The response to the social and physical environment involves two-way communication between the brain and the body and epigenetic adaptation (‘allostasis’) via mediators of the cardiovascular, immune, metabolic, neuroendocrine, and neural mechanisms. Chronic stress causes wear and tear on the brain and body (‘allostatic load and overload’), reflecting also the impact of health-damaging behaviours and lasting effects of early life experiences interacting with genetic predispositions. Hormonal and other mediators of allostasis promote adaptation in the short run but cause allostatic load/overload when they are overused or dysregulated. The brain is key because it determines what is threatening and the physiological and behavioural responses, while showing structural remodelling that affects its function. Besides pharmaceuticals, there are ‘top–down’ interventions, like physical activity, that engage ‘the wisdom of the body’ to change itself, as well as the impact of policies of government and business that encourage individuals to manage their own lives and promote increased ‘healthspan’.

scholarly journals Protective and damaging effects of stress mediators: central role of the brain

2006 ◽  
Vol 8 (4) ◽  
pp. 367-381 ◽  
Keyword(s):  
Prefrontal Cortex ◽  
Chronic Stress ◽  
Allostatic Load ◽  
The Body ◽  
Stressful Events ◽  
Whole Body ◽  
Acute And Chronic Stress ◽  
The Mind ◽  
The Impact ◽  
The Brain

The mind involves the whole body and two-way communication between the brain and the cardiovascular, immune, and other systems via neural and endocrine mechanisms. Stress is a condition of the mind-body interaction, and a factor in the expression of disease that differs among individuals. It is notjust the dramatic stressful events that exact their toll, but rather the many events of daily life that elevate and sustain activities of physiological systems and cause sleep deprivation, overeating, and other health-damaging behaviors, producing the feeling of being "stressed out." Over time, this results in wear and tear on the body which is called "allostatic load," and it reflects not only the impact of life experiences but also of genetic load, individual lifestyle habits reflecting items such as diet, exercise, and substance abuse, and developmental experiences that set life-long patterns of behavior and physiological reactivity. Hormones associated with stress and allostatic load protect the body in the short run and promote adaptation by the process known as allostasis, but in the long run allostatic load causes changes in the body that can lead to disease. The brain is the key organ of stress, allostasis, and allostatic load, because it determines what is threatening and therefore stressful, and also determines the physiological and behavioral responses. Brain regions such as the hippocampus, amygdala, and prefrontal cortex respond to acute and chronic stress by undergoing structural remodeling, which alters behavioral and physiological responses. Translational studies in humans with structural and functional imaging reveal smaller hippocampal volume in stress-related conditions, such as mild cognitive impairment in aging and prolonged major depressive illness, as well as in individuals with low self-esteem. Alterations in amygdala and prefrontal cortex are also reported. Besides pharmaceuticals, approaches to alleviate chronic stress and reduce allostatic load and the incidence of diseases of modern life include lifestyle change, and policies of government and business that would improve the ability of individuals to reduce their own chronic stress burden.

scholarly journals Mindfulness Research Update: 2008

2009 ◽  
Vol 14 (1) ◽  
pp. 10-18 ◽  
Author(s):  
Jeffrey M. Greeson
Keyword(s):  
Quality Of Life ◽  
Stress Reduction ◽  
Mindfulness Meditation ◽  
Stress Hormones ◽  
Theoretical Work ◽  
The Body ◽  
Mindfulness Practice ◽  
Optimal Health ◽  
The Brain

Objective: To briefly review the effects of mindfulness on the mind, the brain, the body, and behavior. Methods: Selective review of MEDLINE, PsycINFO, and Google Scholar databases (2003—2008) using the terms ``mindfulness,'' ``meditation,'' ``mental health,'' ``physical health,'' ``quality of life,'' and ``stress reduction.'' A total of 52 exemplars of empirical and theoretical work were selected for review. Results: Both basic and clinical research indicate that cultivating a more mindful way of being is associated with less emotional distress, more positive states of mind, and better quality of life. In addition, mindfulness practice can influence the brain, the autonomic nervous system, stress hormones, the immune system, and health behaviors, including eating, sleeping, and substance use, in salutary ways. Conclusion: The application of cutting-edge technology toward understanding mindfulness— an ``inner technology''—is elucidating new ways in which attention, awareness, acceptance, and compassion may promote optimal health—in mind, body, relationships, and spirit.

scholarly journals How stress mediators can cumulatively contribute to Alzheimer’s disease An allostatic load approach

2019 ◽  
Vol 13 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Tatiane Martins Matos ◽  
Juliana Nery De Souza-Talarico
Keyword(s):  
Risk Factors ◽  
Cognitive Decline ◽  
Disease Progression ◽  
Chronic Stress ◽  
Allostatic Load ◽  
Stress Hormones ◽  
Modifiable Risk Factors ◽  
Cognitive Changes ◽  
Stress Mediators ◽  
The Impact

ABSTRACT. Allostatic load is defined as the frequent activation of the neuroendocrine, immunological, metabolic and cardiovascular systems, which makes individuals more susceptible to stress-related health problems. According to this model, physiological dysregulations start to emerge decades before diseases manifest. Consequently, stress research has shifted its attention to anticipating the degree of this dysregulation to better understand the impact of stress hormones and other biomarkers on disease progression. In view of the growing number of studies that demonstrate the influence of modifiable risk factors on cognitive decline, in addition to the effects of chronic stress mediators, the objective of the present review was to present an overview of the development of cognitive changes based on studies on stress and its mediators.

scholarly journals Effect of Hemin on Brain Alterations and Neuroglobin Expression in Water Immersion Restraint Stressed Rats

Scientifica ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Merhan Ragy ◽  
Fatma Ali ◽  
Maggie M. Ramzy
Keyword(s):  
Acute Stress ◽  
Water Immersion ◽  
Stress Hormones ◽  
Control Group ◽  
Albino Rats ◽  
Stress Markers ◽  
Stressed Group ◽  
Total Antioxidant ◽  
The Brain ◽  
Blood Brain Barrier Damage

In the brain, the heme oxygenase (HO) system has been reported to be very active and its modulation seems to play a crucial role in the pathophysiology of neurodegenerative disorders. Hemin as HO-1 inducer has been shown to attenuate neuronal injury so the goal of this study was to assess the effect of hemin therapy on the acute stress and how it would modulate neurological outcome. Thirty male albino rats were divided into three groups: control group and stressed group with six-hour water immersion restraint stress (WIRS) and stressed group, treated with hemin, in which each rat received a single intraperitoneal injection of hemin at a dose level of 50 mg/kg body weight at 12 hours before exposure to WIRS. Stress hormones, oxidative stress markers, malondialdehyde (MDA), and total antioxidant capacity (TAC) were measured and expressions of neuroglobin and S100B mRNA in brain tissue were assayed. Our results revealed that hemin significantly affects brain alterations induced by acute stress and this may be through increased expression of neuroglobin and through antioxidant effect. Hemin decreased blood-brain barrier damage as it significantly decreased the expression of S100B. These results suggest that hemin may be an effective therapy for being neuroprotective against acute stress.

scholarly journals Regular exposure to a Citrus-based sensory functional food ingredient alleviates the BOLD brain responses to acute pharmacological stress in a pig model of psychosocial chronic stress

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243893
Author(s):  
Sophie Menneson ◽  
Yann Serrand ◽  
Regis Janvier ◽  
Virginie Noirot ◽  
Pierre Etienne ◽  
...  
Keyword(s):  
Chronic Stress ◽  
Functional Food ◽  
Acute Stress ◽  
Brain Regions ◽  
Stressful Events ◽  
Pharmacological Stress ◽  
Food Ingredient ◽  
Brain Responses ◽  
Potential Benefits ◽  
The Brain

Psychosocial chronic stress is a critical risk factor for the development of mood disorders. However, little is known about the consequences of acute stress in the context of chronic stress, and about the related brain responses. In the present study we examined the physio-behavioural effects of a supplementation with a sensory functional food ingredient (FI) containing Citrus sinensis extract (D11399, Phodé, France) in a pig psychosocial chronic stress model. Female pigs underwent a 5- to 6-week stress protocol while receiving daily the FI (FI, n = 10) or a placebo (Sham, n = 10). We performed pharmacological magnetic resonance imaging (phMRI) to study the brain responses to an acute stress (injection of Synacthen®, a synthetic ACTH-related agonist) and to the FI odour with or without previous chronic supplementation. The olfactory stimulation with the ingredient elicited higher brain responses in FI animals, demonstrating memory retrieval and habituation to the odour. Pharmacological stress with Synacthen injection resulted in an increased activity in several brain regions associated with arousal, associative learning (hippocampus) and cognition (cingulate cortex) in chronically stressed animals. This highlighted the specific impact of acute stress on the brain. These responses were alleviated in animals previously supplemented by the FI during the entire chronic stress exposure. As chronic stress establishes upon the accumulation of acute stress events, any attenuation of the brain responses to acute stress can be interpreted as a beneficial effect, suggesting that FI could be a viable treatment to help individuals coping with repeated stressful events and eventually to reduce chronic stress. This study provides additional evidence on the potential benefits of this FI, of which the long-term consequences in terms of behaviour and physiology need to be further investigated.

scholarly journals Depressed mothers and their offspring differ in terms of health risk profiles and allostatic load

2020 ◽  
Keyword(s):  
Health Risk ◽  
Psychiatric Disorders ◽  
Chronic Stress ◽  
Allostatic Load ◽  
The Body ◽  
Risk Profiles ◽  
Wear And Tear ◽  
Depressed Mothers

Allostatic load is essentially the “wear and tear” that accumulates in the body in individuals exposed to chronic stress. Because some patients with psychiatric disorders have a shorter lifespan than their healthy counterparts,1 some researchers have suggested that there might be a link between disorders such as depression and increased allostatic load.

Interoception, Stress, and Physical Symptoms in Stress-Associated Diseases

2020 ◽  
Vol 27 (4) ◽  
pp. 132-153 ◽  
Author(s):  
André Schulz ◽  
Dana Schultchen ◽  
Claus Vögele
Keyword(s):  
Stress Responses ◽  
Acute Stress ◽  
Physiological Stress ◽  
Current Knowledge ◽  
Physical Symptoms ◽  
The Body ◽  
Body Axis ◽  
Main Hypothesis ◽  
Stress Effects ◽  
The Brain

Abstract. The brain and peripheral bodily organs continuously exchange information. Exemplary, interoception refers to the processing and perception of ascending information from the body to the brain. Stress responses involve a neurobehavioral cascade, which includes the activation of peripheral organs via neural and endocrine pathways and can thus be seen as an example for descending information on the brain-body axis. Hence, the interaction of interoception and stress represents bi-directional communication on the brain-body axis. The main hypothesis underlying this review is that the dysregulation of brain-body communication represents an important mechanism for the generation of physical symptoms in stress-related disorders. The aims of this review are, therefore, (1) to summarize current knowledge on acute stress effects on different stages of interoceptive signal processing, (2) to discuss possible patterns of abnormal brain-body communication (i.e., alterations in interoception and physiological stress axes activation) in mental disorders and chronic physical conditions, and (3) to consider possible approaches to modify interoception. Due to the regulatory feedback loops underlying brain-body communication, the modification of interoceptive processes (ascending signals) may, in turn, affect physiological stress axes activity (descending signals), and, ultimately, also physical symptoms.

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