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Organ and brain crosstalk: The liver-brain axis in gastrointestinal, liver, and pancreatic diseases.Neuropharmacology Mar 2022The liver is the largest organ in the human body and is responsible for the metabolism and storage of the three principal nutrients: carbohydrates, fats, and proteins.... (Review)
Review
The liver is the largest organ in the human body and is responsible for the metabolism and storage of the three principal nutrients: carbohydrates, fats, and proteins. In addition, the liver contributes to the breakdown and excretion of alcohol, medicinal agents, and toxic substances and the production and secretion of bile. In addition to its role as a metabolic centre, the liver has recently attracted attention for its function in the liver-brain axis, which interacts closely with the central nervous system via the autonomic nervous system, including the vagus nerve. The liver-brain axis influences the control of eating behaviour in the central nervous system through stimuli from the liver. Conversely, neural signals from the central nervous system influence glucose, lipid, and protein metabolism in the liver. The liver also receives a constant influx of nutrients and hormones from the intestinal tract and compounds of bacterial origin via the portal system. As a result, the intestinal tract and liver are involved in various immunological interactions. A good example is the co-occurrence of primary sclerosing cholangitis and ulcerative colitis. These heterogeneous roles of the liver-brain axis are mediated via the vagus nerve in an asymmetrical manner. In this review, we provide an overview of these interactions, mainly with the liver but also with the brain and gut.
Topics: Animals; Autonomic Nervous System; Brain; Gastrointestinal Diseases; Humans; Liver; Liver Diseases; Pancreatic Diseases; Vagus Nerve
PubMed: 34919906
DOI: 10.1016/j.neuropharm.2021.108915 -
Neuroscience and Biobehavioral Reviews May 2016The present meta-analysis aimed to quantify current evidence on sex differences in the autonomic control of the heart, indexed by measures of heart rate variability... (Meta-Analysis)
Meta-Analysis Review
The present meta-analysis aimed to quantify current evidence on sex differences in the autonomic control of the heart, indexed by measures of heart rate variability (HRV) in healthy human subjects. An extensive search of the literature yielded 2020 titles and abstracts, of which 172 provided sufficient reporting of sex difference in HRV. Data from 63,612 participants (31,970 females) were available for analysis. Meta-analysis yielded a total of 1154 effect size estimates (k) across 50 different measures of HRV in a cumulated total of 296,247 participants. Females showed a significantly lower mean RR interval and standard deviation of RR intervals (SDNN). The power spectral density of HRV in females is characterized by significantly less total power that contains significantly greater high- (HF) and less low-frequency (LF) power. This is further reflected by a lower LF/HF ratio. Meta-regression revealed significant effects of age, respiration control and the length of recording available for analysis. Although women showed greater mean heart rate, they showed greater vagal activity indexed by HF power of HRV. Underlying mechanisms of these findings are discussed.
Topics: Autonomic Nervous System; Female; Heart Rate; Humans; Male; Sex Characteristics
PubMed: 26964804
DOI: 10.1016/j.neubiorev.2016.03.007 -
European Journal of Clinical... Nov 2019Atrial fibrillation (AF) is the commonest abnormal heart rhythm with significant related morbidity and mortality. Several pathophysiologic mechanisms have been advocated... (Review)
Review
BACKGROUND
Atrial fibrillation (AF) is the commonest abnormal heart rhythm with significant related morbidity and mortality. Several pathophysiologic mechanisms have been advocated to explain the onset of AF. There has been increasing evidence that abnormalities of the autonomic nervous system (ANS) that includes sympathetic, parasympathetic and intrinsic neural network are involved in the pathogenesis of AF. This review will consider the anatomical and pathophysiological concepts of the cardiac neuronal network and discuss how it can be investigated.
DESIGN
Relevant articles for this review were selected primarily from Ovid Medline and Embase databases (see appendix). We searched for key terms "atrial fibrillation," "AF," "autonomic dysfunction," "autonomic nervous system," "heart rate variability" and "HRV" to gather relevant studies. Duplicate papers were excluded.
RESULTS
Heart is richly innervated by autonomic nerves. Both sympathetic and parasympathetic systems interact in developing AF along with cardiac ganglionated plexi (GP). Thus autonomic dysfunction is present in AF. There are methods including selective ablation that reduce autonomic innervation and show to reduce the incidence of spontaneous or induced atrial arrhythmias. Heart rate variability (HRV) is a useful tool to assess sympathetic and parasympathetic influences on disease states. HRV can be improved following intervention and is thus a useful application in assessing autonomic dysfunction in patients with AF.
CONCLUSION
ANS plays a crucial role in the development, propagation and complexity of AF. Assessment of the autonomic involvement in the propagation of AF may help in explaining why certain patients with AF do not benefit from cardioversion or ablation.
Topics: Atrial Fibrillation; Heart; Heart Rate; Humans; Parasympathetic Nervous System; Sympathetic Nervous System
PubMed: 31560809
DOI: 10.1111/eci.13174 -
Autonomic Neuroscience : Basic &... Jul 2023
Topics: Autonomic Nervous System; Stress, Psychological; Allostasis; Stress, Physiological
PubMed: 37257231
DOI: 10.1016/j.autneu.2023.103096 -
Brain and Nerve = Shinkei Kenkyu No... Aug 2022The polyvagal theory, proposed by Stephen Porges, describes the adaptive responses of the mammalian autonomic nervous system. According to this novel theory, the vagus...
The polyvagal theory, proposed by Stephen Porges, describes the adaptive responses of the mammalian autonomic nervous system. According to this novel theory, the vagus nerve functions through two independent pathways, referred to as the ventral and the dorsal vagal pathways. The ventral vagus is a myelinated nerve that has newly emerged in mammals and in coordination with cranial nerves regulates the muscles of the face and head to form the ventral vagal complex, which enables social engagement via exchange of safety cues and downregulating sympathetic defense reaction. In a safe environment, mammals normally adapt using the social engagement system; however, depending on the degree of risk exposure in the environment, activation of the sympathetic nervous system triggers the fight-or-flight response, and the dorsal vagal system initiates the immobilization shutdown response. The involuntary neural process through which the nervous system evaluates risk is referred to as neuroception. The polyvagal theory explains the pathophysiology of trauma and various physical symptoms associated with ventral vagal complex dysfunction. Moreover, this may potentially be useful as a fundamental theory in psychotherapy, in which the quality of social interaction is critical.
Topics: Adaptation, Physiological; Animals; Autonomic Nervous System; Humans; Mammals; Vagus Nerve
PubMed: 35941799
DOI: 10.11477/mf.1416202169 -
Comprehensive Physiology Jul 2015Interaction between the autonomic nervous system and the neuroendocrine system is critical for maintenance of homeostasis in a wide variety of physiological parameters... (Review)
Review
Interaction between the autonomic nervous system and the neuroendocrine system is critical for maintenance of homeostasis in a wide variety of physiological parameters such as body temperature, fluid and electrolyte balance, and blood pressure and volume. The anatomical and physiological mechanisms underlying integration of the neuroendocrine and autonomic mechanisms responsible for eliciting integrated autonomic and neuroendocrine actions are the focus of this article. This includes a focus on the hypothalamic paraventricular nucleus, because it includes both neuroendocrine neurons and preganglionic autonomic neurons that regulate sympathetic and parasympathetic outflow. The "wired" and "nonwired" mechanisms within PVN that facilitate communication between these neuronal populations are described. The impact of peripheral hormones, specifically the adrenal and gonadal steroids, on the neuroendocrine and autonomic systems is discussed, and exercise is used as a specific example of a physiological challenge/stress that requires precise integration of neuroendocrine and autonomic responses to maintain cardiovascular, fluid, and energy homeostasis.
Topics: Animals; Autonomic Nervous System; Homeostasis; Humans; Hypothalamo-Hypophyseal System; Pituitary-Adrenal System
PubMed: 26140719
DOI: 10.1002/cphy.c140028 -
Clinical Autonomic Research : Official... Feb 2023
Topics: Humans; Autonomic Nervous System; Sympathetic Nervous System; Syncope, Vasovagal; Tilt-Table Test; Heart Rate
PubMed: 36538152
DOI: 10.1007/s10286-022-00915-9 -
Handbook of Clinical Neurology 2016Menière's disease (MD) is a chronic multifactorial disorder of the inner ear characterized by episodic vestibular symptoms associated with sensorineural hearing loss,... (Review)
Review
Menière's disease (MD) is a chronic multifactorial disorder of the inner ear characterized by episodic vestibular symptoms associated with sensorineural hearing loss, tinnitus, and aural pressure. Epidemiologic and genomic evidence supports a genetic susceptibility with multiple biochemical pathways involved, including the endocrine system, innate immune response, and autonomic nervous system. Allergens, infectious agents, vascular events, or genetic factors could modify inner-ear homeostasis and trigger MD. The diagnosis of MD is based on clinical criteria and requires the observation of an episodic vertigo syndrome associated with low- to medium-frequency sensorineural hearing loss and fluctuating aural symptoms (hearing loss, tinnitus, and/or fullness) in the affected ear. Headache is also found during the attacks and bilateral involvement is found in 25-40% of cases. Audiologic and vestibular assessment is recommended to monitor the clinical course. The treatment of MD is symptomatic to obtain relief of vestibular episodes and preventive to limit hearing loss progression. Treatment options include sodium restriction, betahistine, intratympanic gentamicin, or steroids and eventually surgery, such as cochlear implantation.
Topics: Audiometry; Autonomic Nervous System; Humans; Meniere Disease
PubMed: 27638077
DOI: 10.1016/B978-0-444-63437-5.00019-4 -
Sub-cellular Biochemistry 2023The vertebrate nervous system is divided into central (CNS) and peripheral (PNS) components. In turn, the PNS is divided into the autonomic (ANS) and enteric (ENS)...
The vertebrate nervous system is divided into central (CNS) and peripheral (PNS) components. In turn, the PNS is divided into the autonomic (ANS) and enteric (ENS) nervous systems. Ageing implicates time-related changes to anatomy and physiology in reducing organismal fitness. In the case of the CNS, there exists substantial experimental evidence of the effects of age on individual neuronal and glial function. Although many such changes have yet to be experimentally observed in the PNS, there is considerable evidence of the role of ageing in the decline of ANS function over time. As such, this chapter will argue that the ANS constitutes a paradigm for the physiological consequences of ageing, as well as for their clinical implications.
Topics: Autonomic Nervous System; Neurons
PubMed: 37120470
DOI: 10.1007/978-3-031-26576-1_10 -
Comprehensive Physiology Jun 2022Acute stroke is one of the leading causes of morbidity and mortality worldwide. Stroke-induced immune-inflammatory response occurs in the perilesion areas and the... (Review)
Review
Acute stroke is one of the leading causes of morbidity and mortality worldwide. Stroke-induced immune-inflammatory response occurs in the perilesion areas and the periphery. Although stroke-induced immunosuppression may alleviate brain injury, it hinders brain repair as the immune-inflammatory response plays a bidirectional role after acute stroke. Furthermore, suppression of the systemic immune-inflammatory response increases the risk of life-threatening systemic bacterial infections after acute stroke. Therefore, it is essential to explore the mechanisms that underlie the stroke-induced immune-inflammatory response. Autonomic nervous system (ANS) activation is critical for regulating the local and systemic immune-inflammatory responses and may influence the prognosis of acute stroke. We review the changes in the sympathetic and parasympathetic nervous systems and their influence on the immune-inflammatory response after stroke. Importantly, this article summarizes the mechanisms on how ANS regulates the immune-inflammatory response through neurotransmitters and their receptors in immunocytes and immune organs after stroke. To facilitate translational research, we also discuss the promising therapeutic approaches modulating the activation of the ANS or the immune-inflammatory response to promote neurologic recovery after stroke. © 2022 American Physiological Society. Compr Physiol 12:3665-3704, 2022.
Topics: Autonomic Nervous System; Brain; Humans; Immune System; Parasympathetic Nervous System; Stroke
PubMed: 35766834
DOI: 10.1002/cphy.c210047