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Neuroscience Bulletin Feb 2019The autonomic nervous system controls various internal organs and executes crucial functions through sophisticated neural connectivity and circuits. Its dysfunction... (Review)
Review
The autonomic nervous system controls various internal organs and executes crucial functions through sophisticated neural connectivity and circuits. Its dysfunction causes an imbalance of homeostasis and numerous human disorders. In the past decades, great efforts have been made to study the structure and functions of this system, but so far, our understanding of the classification of autonomic neuronal subpopulations remains limited and a precise map of their connectivity has not been achieved. One of the major challenges that hinder rapid progress in these areas is the complexity and heterogeneity of autonomic neurons. To facilitate the identification of neuronal subgroups in the autonomic nervous system, here we review the well-established and cutting-edge technologies that are frequently used in peripheral neuronal tracing and profiling, and discuss their operating mechanisms, advantages, and targeted applications.
Topics: Animals; Autonomic Nervous System; Cell Differentiation; Cell Lineage; Homeostasis; Humans; Nervous System; Neurons
PubMed: 30171526
DOI: 10.1007/s12264-018-0284-9 -
Clinical Autonomic Research : Official... Dec 2016The aim of this study is to review the evidence on the role of the autonomic nervous system as a determinant of brain volume. Brain volume measures have gained... (Review)
Review
OBJECTIVE
The aim of this study is to review the evidence on the role of the autonomic nervous system as a determinant of brain volume. Brain volume measures have gained increasing attention given its biological importance, particularly as a measurement of neurodegeneration.
METHODS
Using an integrative approach, we reviewed publications addressing the anatomical and physiological characteristics of brain autonomic innervation focusing on evidence from diverse clinical populations with respect to brain volume.
RESULTS
Multiple mechanisms contribute to changes in brain volume. Autonomic influence on cerebral blood volume is of significant interest.
CONCLUSION
We suggest a role for the autonomic innervation of brain vessels in fluctuations of cerebral blood volume. Further investigation in several clinical populations including multiple sclerosis is warranted to understand the specific role of parenchyma versus blood vessels changes on final brain volume.
Topics: Autonomic Nervous System; Autonomic Nervous System Diseases; Brain; Cerebrovascular Circulation; Humans
PubMed: 27568208
DOI: 10.1007/s10286-016-0380-8 -
Ageing Research Reviews Dec 2018An ageing myocardium possesses significant electrophysiological alterations that predisposes the elderly patient to arrhythmic risk. Whilst these alterations are... (Review)
Review
An ageing myocardium possesses significant electrophysiological alterations that predisposes the elderly patient to arrhythmic risk. Whilst these alterations are intrinsic to the cardiac myocytes, they are modulated by the cardiac autonomic nervous system (ANS) and consequently, ageing of the cardiac ANS is fundamental to the development of arrhythmias. A systems-based approach that incorporates the influence of the cardiac ANS could lead to better mechanistic understanding of how arrhythmogenic triggers and substrates interact spatially and temporally to produce sustained arrhythmia and why its incidence increases with age. Despite the existence of physiological oscillations of ANS activity on the heart, pathological oscillations can lead to defective activation and recovery properties of the myocardium. Such changes can be attributable to the decrease in functionality and structural alterations to ANS specific receptors in the myocardium with age. These altered ANS adaptive responses can occur either as a normal ageing process or accelerated in the presence of specific cardiac pathologies, such as genetic mutations or neurodegenerative conditions. Targeted intervention that seek to manipulate the ageing ANS influence on the myocardium may prove to be an efficacious approach for the management of arrhythmia in the ageing population.
Topics: Aging; Animals; Arrhythmias, Cardiac; Autonomic Nervous System; Brain; Heart; Humans; Myocardium
PubMed: 30300712
DOI: 10.1016/j.arr.2018.09.005 -
The New England Journal of Medicine Jan 2020
Review
Topics: Autonomic Nervous System; Baroreflex; Humans; Neurons, Afferent; Neurons, Efferent; Primary Dysautonomias
PubMed: 31914243
DOI: 10.1056/NEJMra1509723 -
Circulation Research Jun 2019Hypertension affects an estimated 103 million Americans, yet gaps in knowledge continue to limit its successful management. Rapidly emerging evidence is linking gut... (Review)
Review
Hypertension affects an estimated 103 million Americans, yet gaps in knowledge continue to limit its successful management. Rapidly emerging evidence is linking gut dysbiosis to many disorders and diseases including hypertension. The evolution of the -omics techniques has allowed determination of the abundance and potential function of gut bacterial species by next-generation bacterial sequencing, whereas metabolomics techniques report shifts in bacterial metabolites in the systemic circulation of hypertensive patients and rodent models of hypertension. The gut microbiome and host have evolved to exist in balance and cooperation, and there is extensive crosstalk between the 2 to maintain this balance, including during regulation of blood pressure. However, an understanding of the mechanisms of dysfunctional host-microbiome interactions in hypertension is still lacking. Here, we synthesize some of our recent data with published reports and present concepts and a rationale for our emerging hypothesis of a dysfunctional gut-brain axis in hypertension. Hopefully, this new information will improve the understanding of hypertension and help to address some of these knowledge gaps.
Topics: Animals; Autonomic Nervous System; Blood Pressure; Gastrointestinal Microbiome; Gastrointestinal Tract; Humans; Hypertension
PubMed: 31219753
DOI: 10.1161/CIRCRESAHA.119.313965 -
Best Practice & Research. Clinical... Oct 2017Joint homeostasis is affected by local and systemic processes. Catecholaminergic and cholinergic fibers innervate the synovium, trabecular bone, and periosteum. Several... (Review)
Review
Joint homeostasis is affected by local and systemic processes. Catecholaminergic and cholinergic fibers innervate the synovium, trabecular bone, and periosteum. Several studies have investigated the involvement of the autonomic nervous system (ANS) in joint homeostasis and the pathophysiology of osteoarthritis (OA). Various resident cells of osteoarticular tissues express receptors for sympathetic and parasympathetic neurotransmitters (norepinephrine/epinephrine and acetylcholine, respectively), which enables them to respond to autonomic stimuli. Furthermore, some of these cells are also able to synthesize neurotransmitters locally and secrete them, which may then act locally regardless of autonomic innervation. The sympathetic nervous system (SNS) is known for promoting bone loss, which has also been demonstrated in the subchondral bone during OA. However, it could interfere with other mechanisms in joint homeostasis. Indeed, intake of beta-blockers decreases pain sensation in individuals with OA; hence, the SNS could be one of the systemic links between hypertension and OA. Parasympathetic fibers may also be implicated in joint homeostasis and local control of inflammation. The vagus nerve has been found to have a strong anti-inflammatory action in other rheumatic diseases through the nicotinic alpha-7 receptor, which is locally expressed by most joint resident cells. Altogether, these data suggest that the ANS is involved in joint homeostasis and OA pathogenesis.
Topics: Autonomic Nervous System; Humans; Osteoarthritis
PubMed: 30509412
DOI: 10.1016/j.berh.2018.04.001 -
Current Neurology and Neuroscience... Sep 2018Patients with Parkinson's disease (PD) often display gastrointestinal and genitourinary autonomic symptoms years or even decades prior to diagnosis. These symptoms are... (Review)
Review
PURPOSE OF REVIEW
Patients with Parkinson's disease (PD) often display gastrointestinal and genitourinary autonomic symptoms years or even decades prior to diagnosis. These symptoms are thought to be caused in part by pathological α-synuclein inclusions in the peripheral autonomic and enteric nervous systems. It has been proposed that the initial α-synuclein aggregation may in some PD patients originate in peripheral nerve terminals and then spread centripetally to the spinal cord and brainstem. In vivo imaging methods can directly quantify the degeneration of the autonomic nervous system as well as the functional consequences such as perturbed motility. Here, we review the methodological principles of these imaging techniques and the major findings in patients with PD and atypical parkinsonism.
RECENT FINDINGS
Loss of sympathetic and parasympathetic nerve terminals in PD can be visualized using radiotracer imaging, including I-MIBG scintigraphy, and F-dopamine and C-donepezil PET. Recently, ultrasonographical studies disclosed reduced diameter of the vagal nerves in PD patients. Radiological and radioisotope techniques have demonstrated dysmotility and prolonged transit time throughout all subdivisions of the gastrointestinal tract in PD. The prevalence of objective dysfunction as measured with these imaging methods is often considerably higher compared to the prevalence of subjective symptoms experienced by the patients. Degeneration of the autonomic nervous system may play a key role in the pathogenesis of PD. In vivo imaging techniques provide powerful and noninvasive tools to quantify the degree and extent of this degeneration and its functional consequences.
Topics: Autonomic Nervous System; Humans; Parkinson Disease; Parkinsonian Disorders; Positron-Emission Tomography; Radionuclide Imaging; Tomography, Emission-Computed, Single-Photon
PubMed: 30232650
DOI: 10.1007/s11910-018-0889-4 -
Current Pharmaceutical Design 2017Although evidence over the last 30 years suggests that the autonomic nervous system (ANS) mediates stress-induced allostatic and immune responses, the crucial role that... (Review)
Review
Although evidence over the last 30 years suggests that the autonomic nervous system (ANS) mediates stress-induced allostatic and immune responses, the crucial role that it plays in the tumor micro-environment has only recently been reported. Here, we review the action of ANS signaling in this micro-environment. Emerging data suggest that primary tumors are innervated by the ANS which mediates stress-related effects on tumor progression. The activation of the sympathetic nervous system (SNS) takes advantage of neurotransmitters and neuropeptides from the innervating neural circuitry and/or hypothalamic-pituitary-adrenal axis glucocorticoids via their receptors to modulate the gene expression associated with oncogenesis, the proliferation and apoptosis of tumor cells, angiogenesis, and the tumor-associated immune response. The parasympathetic nervous system has also been implicated in some tumor types, but its contribution in the tumor micro-environment remains unclear. In addition to identifying the ANS signaling pathways involved in tumor progression, recent reports suggest that the ANS could be a potential biomarker to predict tumor progression, and have identified new pharmacological strategies, such as the use of β-adrenergic blockers, to inhibit tumor progression and metastasis by targeting this system. These findings are reviewed here.
Topics: Autonomic Nervous System; Humans; Neoplasms; Tumor Microenvironment
PubMed: 27784236
DOI: 10.2174/1381612822666161025152942 -
International Journal of Cardiology Jul 2019Atrial fibrillation is the most common sustained arrhythmia and is associated with significant morbidity and mortality. The autonomic nervous system has a significant... (Review)
Review
Atrial fibrillation is the most common sustained arrhythmia and is associated with significant morbidity and mortality. The autonomic nervous system has a significant role in the milieu predisposing to the triggers, perpetuators and substrate for atrial fibrillation. It has direct electrophysiological effects and causes alterations in atrial structure. In a significant portion of patients with atrial fibrillation, the autonomic nervous system activity is likely a composite of reflex excitation due to atrial fibrillation itself and contribution of concomitant risk factors such as hypertension, obesity and sleep-disordered breathing. We review the role of autonomic nervous system activation, with focus on changes in reflex control during atrial fibrillation and the role of combined sympatho-vagal activation for atrial fibrillation initiation, maintenance and progression. Finally, we discuss the potential impact of combined aggressive risk factor management as a strategy to modify the autonomic nervous system in patients with atrial fibrillation and to reverse the arrhythmogenic substrate.
Topics: Atrial Fibrillation; Autonomic Nervous System; Heart Atria; Heart Rate; Humans; Risk Factors; Sympathectomy
PubMed: 30497894
DOI: 10.1016/j.ijcard.2018.11.091 -
Peptides Apr 2022Aging is the greatest independent risk factor for developing hypertension and cardiovascular-related diseases including systolic hypertension, vascular disease, ischemic... (Review)
Review
Aging is the greatest independent risk factor for developing hypertension and cardiovascular-related diseases including systolic hypertension, vascular disease, ischemic events, arrhythmias, and heart failure. Age-related cardiovascular risk is associated with dysfunction of peripheral organ systems, such as the heart and vasculature, as well as an imbalance in the autonomic nervous system characterized by increased sympathetic and decreased parasympathetic neurotransmission. Given the increasing prevalence of aged individuals worldwide, it is critical to better understand mechanisms contributing to impaired cardiovascular autonomic control in this population. In this regard, the renin-angiotensin system has emerged as an important hormonal modulator of cardiovascular function in aging, in part through modulation of autonomic pathways controlling sympathetic and parasympathetic outflow to cardiovascular end organs. This review will summarize the role of the RAS in cardiovascular autonomic control during aging, with a focus on current knowledge of angiotensin II versus angiotensin-(1-7) pathways in both rodent models and humans, pharmacological treatment strategies targeting the renin-angiotensin system, and unanswered questions for future research.
Topics: Aged; Aging; Autonomic Nervous System; Cardiovascular Diseases; Cardiovascular System; Humans; Hypertension; Renin-Angiotensin System; Sympathetic Nervous System
PubMed: 34973286
DOI: 10.1016/j.peptides.2021.170733