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Comprehensive Physiology Jun 2016Comprised of the sympathetic nervous system, parasympathetic nervous system, and enteric nervous system, the autonomic nervous system (ANS) provides the neural control... (Review)
Review
Comprised of the sympathetic nervous system, parasympathetic nervous system, and enteric nervous system, the autonomic nervous system (ANS) provides the neural control of all parts of the body except for skeletal muscles. The ANS has the major responsibility to ensure that the physiological integrity of cells, tissues, and organs throughout the entire body is maintained (homeostasis) in the face of perturbations exerted by both the external and internal environments. Many commonly prescribed drugs, over-the-counter drugs, toxins, and toxicants function by altering transmission within the ANS. Autonomic dysfunction is a signature of many neurological diseases or disorders. Despite the physiological relevance of the ANS, most neuroscience textbooks offer very limited coverage of this portion of the nervous system. This review article provides both historical and current information about the anatomy, physiology, and pharmacology of the sympathetic and parasympathetic divisions of the ANS. The ultimate aim is for this article to be a valuable resource for those interested in learning the basics of these two components of the ANS and to appreciate its importance in both health and disease. Other resources should be consulted for a thorough understanding of the third division of the ANS, the enteric nervous system. © 2016 American Physiological Society. Compr Physiol 6:1239-1278, 2016.
Topics: Autonomic Fibers, Postganglionic; Autonomic Fibers, Preganglionic; Autonomic Nervous System; Humans; Norepinephrine; Parasympathetic Nervous System; Receptors, Cholinergic; Sympathetic Nervous System; Synaptic Transmission
PubMed: 27347892
DOI: 10.1002/cphy.c150037 -
Nature Reviews. Gastroenterology &... Jun 2020The gastrointestinal tract is the only internal organ to have evolved with its own independent nervous system, known as the enteric nervous system (ENS). This Review... (Review)
Review
The gastrointestinal tract is the only internal organ to have evolved with its own independent nervous system, known as the enteric nervous system (ENS). This Review provides an update on advances that have been made in our understanding of how neurons within the ENS coordinate sensory and motor functions. Understanding this function is critical for determining how deficits in neurogenic motor patterns arise. Knowledge of how distension or chemical stimulation of the bowel evokes sensory responses in the ENS and central nervous system have progressed, including critical elements that underlie the mechanotransduction of distension-evoked colonic peristalsis. Contrary to original thought, evidence suggests that mucosal serotonin is not required for peristalsis or colonic migrating motor complexes, although it can modulate their characteristics. Chemosensory stimuli applied to the lumen can release substances from enteroendocrine cells, which could subsequently modulate ENS activity. Advances have been made in optogenetic technologies, such that specific neurochemical classes of enteric neurons can be stimulated. A major focus of this Review will be the latest advances in our understanding of how intrinsic sensory neurons in the ENS detect and respond to sensory stimuli and how these mechanisms differ from extrinsic sensory nerve endings in the gut that underlie the gut-brain axis.
Topics: Afferent Pathways; Autonomic Fibers, Preganglionic; Efferent Pathways; Enteric Nervous System; Enteroendocrine Cells; Gastrointestinal Motility; Humans; Mechanotransduction, Cellular; Myoelectric Complex, Migrating; Neural Pathways; Neurons; Neurotransmitter Agents; Sensation; Sensory Receptor Cells; Serotonin
PubMed: 32152479
DOI: 10.1038/s41575-020-0271-2 -
Nature Neuroscience Aug 2019The effects of autonomic innervation of tumors on tumor growth remain unclear. Here we developed a series of genetic techniques to manipulate autonomic innervation in a...
The effects of autonomic innervation of tumors on tumor growth remain unclear. Here we developed a series of genetic techniques to manipulate autonomic innervation in a tumor- and fiber-type-specific manner in mice with human breast cancer xenografts and in rats with chemically induced breast tumors. Breast cancer growth and progression were accelerated following stimulation of sympathetic nerves in tumors, but were reduced following stimulation of parasympathetic nerves. Tumor-specific sympathetic denervation suppressed tumor growth and downregulated the expression of immune checkpoint molecules (programed death-1 (PD-1), programed death ligand-1 (PD-L1), and FOXP3) to a greater extent than with pharmacological α- or β-adrenergic receptor blockers. Genetically induced simulation of parasympathetic innervation of tumors decreased PD-1 and PD-L1 expression. In humans, a retrospective analysis of breast cancer specimens from 29 patients revealed that increased sympathetic and decreased parasympathetic nerve density in tumors were associated with poor clinical outcomes and correlated with higher expression of immune checkpoint molecules. These findings suggest that autonomic innervation of tumors regulates breast cancer progression.
Topics: Adrenergic Antagonists; Animals; Autonomic Fibers, Preganglionic; B7-H1 Antigen; Breast Neoplasms; Denervation; Disease Progression; Female; Forkhead Transcription Factors; Heterografts; Humans; Mice; Mice, Inbred BALB C; Neoplasm Transplantation; Parasympathetic Nervous System; Programmed Cell Death 1 Receptor; Rats; Retrospective Studies; Stress, Psychological; Sympathetic Nervous System
PubMed: 31285612
DOI: 10.1038/s41593-019-0430-3 -
Clinical Autonomic Research : Official... Feb 2019To review the currently available literature on clinical autonomic tests of sudomotor function. (Review)
Review
PURPOSE
To review the currently available literature on clinical autonomic tests of sudomotor function.
METHODS
We searched PubMED/MEDLINE for articles on technical principles and clinical applications of sudomotor tests with a focus on their drawbacks and perspectives in order to provide a narrative review.
RESULTS
The quantitative sudomotor axon reflex sweat test (QSART) is the most widely used test of sudomotor function. The technique captures pathology with low intra- and inter-subject variability but is limited by technical demands. The thermoregulatory sweat test comprises topographic sweat pattern analysis of the ventral skin surface and allows differentiating preganglionic from postganglionic sudomotor damage when combined with a small fiber test such as QSART. The sympathetic skin response also belongs to the more established techniques and is used in lie detection systems due to its high sensitivity for sudomotor responses to emotional stimuli. However, its clinical utility is limited by high variability of measurements, both within and between subjects. Newer and, therefore, less widely established techniques include silicone impressions, quantitative direct and indirect axon reflex testing, sensitive sweat test, and measurement of electrochemical skin conductance. The spoon test does not allow a quantitative assessment of the sweat response but can be used as bedside-screening tool of sudomotor dysfunction.
CONCLUSION
While new autonomic sudomotor function testings have been developed and studied over the past decades, the most were well-studied and established techniques QSART and TST remain the gold standard of sudomotor assessment. Combining these techniques allows for sophisticated analysis of neurally mediated sudomotor impairment. However, newer techniques display potential to complement gold standard techniques to further improve their precision and diagnostic value.
Topics: Animals; Axons; Body Temperature Regulation; Galvanic Skin Response; Humans; Skin Physiological Phenomena; Sweat Glands; Sweating
PubMed: 29737432
DOI: 10.1007/s10286-018-0530-2 -
Autonomic Neuroscience : Basic &... Aug 2016The autonomic nervous system controls the heart by dynamic recruitment and withdrawal of cardiac parasympathetic and sympathetic activities. These activities are... (Review)
Review
The autonomic nervous system controls the heart by dynamic recruitment and withdrawal of cardiac parasympathetic and sympathetic activities. These activities are generated by groups of sympathoexcitatory and vagal preganglionic neurones residing in a close proximity to each other within well-defined structures of the brainstem. This short essay provides a general overview and an update on the latest developments in our understanding of the central nervous origins and functional significance of cardiac vagal tone. Significant experimental evidence suggests that distinct groups of cardiac vagal preganglionic neurones with different patterns of activity control nodal tissue (controlling the heart rate and atrioventricular conductance) and the ventricular myocardium (modulating its contractility and excitability).
Topics: Animals; Autonomic Fibers, Preganglionic; Heart; Heart Rate; Humans; Medulla Oblongata; Neurons; Vagus Nerve
PubMed: 27396874
DOI: 10.1016/j.autneu.2016.06.003