Study The Association Between The Gut Microbiota And Brain Function

Stress has a huge impact on the immune system. The immune system is interconnected. For example the immune, nervous, and endocrine system is linked through specialized communication pathways involving hormones, neurotransmitters, neuropeptides, and immune cell productions. Stress reactions can directly affect the various response systems and how they handle the neuroendocrine-products. This stress reaction directly affects the hypothalamus and pituitary peptides through the sympathetic branch of the autonomic nervous system. Some of these stressors might be life events, anxiety, and excitements.

Sir William Osler in 1892 first described a condition, which he termed “mucous colitis,” having features that we now describe as IBS, and occurring mostly in women with psychological disturbances. Elucidation of the pathophysiology underlying IBS is a still a work-in-progress, but much has been discovered about the etiology since Osler’s first description. IBS is best understood as a group of symptoms resulting from the interaction between multiple physiologic determinants and psychosocial factors. Physiological mechanisms involved in the pathogenesis include altered gastrointestinal (GI) motility, visceral hyperalgesia, abnormalities in brain-gut interaction, and aberrant central processing of visceral pain. Recent research suggests that previous GI infection, immunological activation, and colonic microbiota may also be important in the pathogenesis of IBS. The impact of stress on these physiological factors is thought to be particularly important in the pathophysiology of IBS, and will be discussed in more detail later on.

The physiological and behavioral effects of early life stress (ELS) on the developing and adult brain are a subject of great interest in the field of neuroscience today. The ability to delineate the mechanisms and structures that are affected during postnatal exposure to chronic stress has the potential to provide invaluable insight into the development of a multitude of neuropsychiatric disorders. While we have come to understand a few of the mechanisms involved in many of these illnesses – such as the significance of the serotonin (5-hydroxytryptamine, 5-HT) neurotransmitter in many depression cases – the complex nature of these disorders and our ability to effectively treat them remains elusive. Such an understanding of how the brain adapts and differentially develops as a result of chronic stress, particularly in early life, may also be able to broaden our understanding of the way in which the brain codes and responds to a variety of emotional triggers.

Bacteria, fungi, viruses and other organisms that make up the digestive system of our body actually outnumber the quantity of our cells. Over time research has made clear that these small organisms play a very important role in our health - both physically and mentally. All these microbes that inhabit our body are called microbiome, and they are estimated to weigh between two to six pounds. Most of these microbes live in our gut and intestines and they help us digest food, incorporate vitamins, and fight infections. Recent studies have revealed that bacteria in our digestive system not only affect our physical health, but it also plays a major role in our mental health. Gut microbiome has been linked to a range of complex behaviors, such

Scientific evidence shows that stress can destroy the beneficial bacteria found within the gut. One study showed that during an exam week, stool samples taken from university students contained fewer of the lactobacilli bacteria than they had during the relatively untroubled first days of the semester. These stress-induced changes to the microbiome then impact the brain and behavior due to defensive molecules produced in the gut during stress. These defensive molecules disrupt the brain neurochemistry and can make you more vulnerable to anxiety and

After birth, stress continues to affect infants and young children in comparable ways when they exposed to stress. The hypothalamic-pituitary-adrenocortical (HPA) axis (the body 's regulatory system that integrates the nervous system with the endocrine system and controls reactions to stress) matures significantly during the early childhood. Exposure to stress early in life has programming effects on the brain (hippocampus, frontal cortex, and amygdala) and chronic stress changes HPA functioning by altering the neurological circuitry, in part through its effects on the limbic and cortical processes (Ulrich-Lai & Herman. 2009). The behaviors correlated with disrupted HPA activity include heightened vigilance and

In addition to the acute response to stress that is generated by the sympathetic nervous system, the hypothalamus-pituitary-adrenal (HPA) axis is activated during initial onset of stress. The HPA axis relies on the hypothalamus to stimulate the pituitary gland to release an adrenocorticotropic hormone (ACTH) before it signals the adrenal cortex to secrete a glucocorticoid, also known as the stress hormone cortisol, resulting in increased blood sugar and metabolic activity within the body. Although the HPA axis initially responds slower than the sympathetic nervous system to stressful events, the HPA axis becomes the more dominant system the longer undergoes sustained stress and anxiety (Kalat, 2013). When periods of stress persist, both the sympathetic nervous system and the HPA axis continue to secrete additional glucocorticoids, as well as catecholamine hormones, both of which activate the receptors of immune cells. The motor vagus fiber then is able to secrete additional catecholamines, specifically noradrenaline and adrenaline, which initiate change to cytokine functions in the immune system as well. “It is suggested that the chronic stress inhibits proinflammatory cytokines secretion which mediate the cellular immunity, while the stress can also activate

In the abstract, The microbiome: stress, health and disease, it says that bacterial colonisation has a great roles in the gut, the role is the development and maturation of the key systems that influence the CNS programming and signaling, this also consists of the immune and endocrine systems. Alone, they have involved neuropathology of several CNS disorders and form an important communication between the microbiota and the brain in health and disease. Moloney, R.D. et al.’s (2014) write that “research has focused on how the microbiota communicates with the CNS and thereby influence brain function” (Moloney, 2014). These communications are not yet explicated but have neural, humoral, immune and metabolic pathways. The studies on germ-free animals

In the abstract on, Gut microbiota and brain function: An evolving field in neuroscience, there is a growing acceptance for the gut microbiota for health and diseases. Foster, J.A., Lyte, M., Meyer, E., and Cryan, J.F. (2015) are demonstrating the role microbiota helps with common health disorders and obesity. Foster, J.A. et al.’s (2015) findings also attracted the attention of neuroscientists and psychiatrists because gut microbiota has a role in brain function for behavior and mental health. World Congress held a symposium in Vancouver, Canada in June 2014 on how gut microbiota effects brain function, behavior and disease. The symposium that took place in Vancouver included many topics; this includes “gut microbiota and neuroendocrine functions,

The abstract on, Mind-altering microorganisms: the impact of the gut microbiota on brain and behavior, gut microbiota has been a major interest in biology in the resent years. The studies of gut microbiota have been showing variations and changes in the influence of normal physiology and diseases from inflammation to obesity. Data collected on the gut microbiota says it communicates with the central nervous system (CNS), through neural, endocrine and immune pathways; this in turn influences brain function and behavior. Cryan, J.F. and Dinan, T.G., studied on animals’ that were germ-free and exposed to pathogenic bacteria had a role for the gut microbiota with anxiety, mood, cognition and pain through probiotic bacteria or antibiotic drugs.

In the abstract, Gut-brain axis: how the microbiome influences anxiety and depression, the abstract says that humans are colonized by commensal intestinal microbiota in the first few days of life. It also says that findings have shown that microbiota’s are important in normal healthy brain functions. Foster, J.A. and McVey Neufeld, K.A. (2013) discussed relations between stress and microbiota, and also how alterations influence stress-related behaviors.

Gut microbiota represents a complex community in human intestines that aids in sustaining a dynamic metabolic ecological equilibrium, thus any changes in those beneficial bacteria (which may be sparked by the infection, illness, drugs and/or stress) have the propensity to substantially affect the health of individuals. It has been shown that these microorganisms are capable of producing and conveying various neuroactive substances such as gamma-aminobutyric acid and serotonin. The gut-brain axis is a quite novel term used to describe the communication between the central and the enteric nervous system, linking emotional and cognitive centres of the brain with peripheral intestinal functions. Recent advances in research have described the importance of gut microbiota in influencing these interactions, and it has been shown that microorganisms can affect the development and function of the central nervous system via the aforementioned gut-brain axis.

Your Backup Brain recalls the author’s time spent interviewing Michael Gershon and other researchers who are pioneering research into the enteric nervous system (ENS). This system, born in the embryonic stage as part of the neural crest and then migrate to what becomes our intestines, they theorize reacts sympathetically to the food we ingest and its own flora and thereby influence our mood and emotions. The article cites several studies both with people and mice that demonstrated some connection between the food that was consumed and emotion. In some case the food seemed to trigger some emotions and in others emotions caused the subjects to gravitate to certain foods. In studying these interactions all of the focus is not just on the food we eat but discussion includes the impact the bacteria, called the gut biome, and its effects on us as well. Theories include that the change in the human diet away from food preserved by fermentation has resulted in the change of the gut biome and possibly contributes to the increases we see in some maladies. While the jury is still out on how the ENS affects the central nervous system and vice versa, clearly the current body of knowledge shows that there are more questions to be asked and answered.

Numerous small molecules are already known to be produced by the human microbiota. Some have been show to affect immune modulation and signaling, which has the potential to influence mood and behavior; they can even regulate the production or the metabolism of neuromodulators and neurotransmitters such as serotonin, dopamine and GABA, all of which are well

Stress is one of the most important factors responsible for depressive disorders [11]. The chronic mild stress (CMS) model, a widely used rodent model of depression, consists of repeated exposure to an array of varying and unpredictable, mild stressors and it induces changes in hypothalamic-pituitary-adrenal (HPA) axis Katz et al. 1981Vollmayr B, Henn FA (2003)