Muscarinic Receptor Subtypes in the GI Tract

Muscarinic Receptor Subtypes in the GI Tract PDF Author: G. Lux
Publisher: Springer Science & Business Media
ISBN: 3642706681
Category : Medical
Languages : en
Pages : 95

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Book Description
The differentiation between the muscarinic and the nicotinic ef fects of acetylcholine led to the subdivision of the cholinergic ner vous system into two categories. Further studies showed that stimu lating and inhibiting muscarinic effects could be demonstrated in different organs. For instance, gastric secretion and gastrointestinal motility are stimulated, while heart rate and the vascular muscula ture are inhibited. For decades, it could not be determined whether the various ef fects were mediated by different subgroups of muscarinic receptors, but eventually, with the availability of agonists and antagonists to muscarinic receptors, and using various techniques, the existence of at least two such subgroups could be ascertained . . Mt receptors are defined by their high affinity for the antagonist pirenzipine in comparison to M2 receptors. This subdivision of muscarinic receptors has since been proved beyond doubt by experi ments in vivo and in vitro, by receptor binding studies, by histoauto radiography, and by electrophysiological studies. However, these different classes of muscarinic receptors have not been found to relate to different types of effects; instead both excit atory and inhibitory effects appear to be linked to each class. For ex ample, excitation of gut motility and inhibition of cardiac contrac tile activities both appear to be mediated by M2 receptors, while ex citation of some nerves in sympathetic ganglia and inhibition of some myenteric nerves may be mediated by M receptors.

Muscarinic Receptor Subtypes in the GI Tract

Muscarinic Receptor Subtypes in the GI Tract PDF Author: G. Lux
Publisher: Springer Science & Business Media
ISBN: 3642706681
Category : Medical
Languages : en
Pages : 95

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Book Description
The differentiation between the muscarinic and the nicotinic ef fects of acetylcholine led to the subdivision of the cholinergic ner vous system into two categories. Further studies showed that stimu lating and inhibiting muscarinic effects could be demonstrated in different organs. For instance, gastric secretion and gastrointestinal motility are stimulated, while heart rate and the vascular muscula ture are inhibited. For decades, it could not be determined whether the various ef fects were mediated by different subgroups of muscarinic receptors, but eventually, with the availability of agonists and antagonists to muscarinic receptors, and using various techniques, the existence of at least two such subgroups could be ascertained . . Mt receptors are defined by their high affinity for the antagonist pirenzipine in comparison to M2 receptors. This subdivision of muscarinic receptors has since been proved beyond doubt by experi ments in vivo and in vitro, by receptor binding studies, by histoauto radiography, and by electrophysiological studies. However, these different classes of muscarinic receptors have not been found to relate to different types of effects; instead both excit atory and inhibitory effects appear to be linked to each class. For ex ample, excitation of gut motility and inhibition of cardiac contrac tile activities both appear to be mediated by M2 receptors, while ex citation of some nerves in sympathetic ganglia and inhibition of some myenteric nerves may be mediated by M receptors.

Muscarinic Receptors

Muscarinic Receptors PDF Author: Allison D. Fryer
Publisher: Springer Science & Business Media
ISBN: 3642232744
Category : Medical
Languages : en
Pages : 501

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Book Description
Muscarinic acetylcholine receptors have played a key role in the advancement of knowledge of pharmacology and neurotransmission since the inception of studies in these fields, and the effects of naturally occurring drugs acting on muscarinic receptors were known and exploited for both therapeutic and non-therapeutic purposes for hundreds of years before the existence of the receptors themselves was recognized. This volume presents a broad yet detailed review of current knowledge of muscarinic receptors that will be valuable both to long-time muscarinic investigators and to those new to the field. It describes the detailed insights that have been obtained on the structure, function, and cell biology of muscarinic receptors. This volume also describes physiological analyses of muscarinic receptors and their roles in regulating the function of the brain and of a variety of peripheral tissues. This volume shows how the study of muscarinic receptors continues to provide new and surprising insights not just to the cholinergic system but to the broad areas of neurobiology, cell biology, pharmacology, and therapeutics.

Enteric Glia

Enteric Glia PDF Author: Brian D. Gulbransen
Publisher: Biota Publishing
ISBN: 1615046615
Category : Medical
Languages : en
Pages : 72

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Book Description
The enteric nervous system (ENS) is a complex neural network embedded in the gut wall that orchestrates the reflex behaviors of the intestine. The ENS is often referred to as the “little brain” in the gut because the ENS is more similar in size, complexity and autonomy to the central nervous system (CNS) than other components of the autonomic nervous system. Like the brain, the ENS is composed of neurons that are surrounded by glial cells. Enteric glia are a unique type of peripheral glia that are similar to astrocytes of the CNS. Yet enteric glial cells also differ from astrocytes in many important ways. The roles of enteric glial cell populations in the gut are beginning to come to light and recent evidence implicates enteric glia in almost every aspect of gastrointestinal physiology and pathophysiology. However, elucidating the exact mechanisms by which enteric glia influence gastrointestinal physiology and identifying how those roles are altered during gastrointestinal pathophysiology remain areas of intense research. The purpose of this e-book is to provide an introduction to enteric glial cells and to act as a resource for ongoing studies on this fascinating population of glia. Table of Contents: Introduction / A Historical Perspective on Enteric Glia / Enteric Glia: The Astroglia of the Gut / Molecular Composition of Enteric Glia / Development of Enteric Glia / Functional Roles of Enteric Glia / Enteric Glia and Disease Processes in the Gut / Concluding Remarks / References / Author Biography

Colonic Motility

Colonic Motility PDF Author: Sushil K. Sarna
Publisher: Biota Publishing
ISBN: 1615041516
Category : Medical
Languages : en
Pages : 159

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Book Description
Three distinct types of contractions perform colonic motility functions. Rhythmic phasic contractions (RPCs) cause slow net distal propulsion with extensive mixing/turning over. Infrequently occurring giant migrating contractions (GMCs) produce mass movements. Tonic contractions aid RPCs in their motor function. The spatiotemporal patterns of these contractions differ markedly. The amplitude and distance of propagation of a GMC are several-fold larger than those of an RPC. The enteric neurons and smooth muscle cells are the core regulators of all three types of contractions. The regulation of contractions by these mechanisms is modifiable by extrinsic factors: CNS, autonomic neurons, hormones, inflammatory mediators, and stress mediators. Only the GMCs produce descending inhibition, which accommodates the large bolus being propelled without increasing muscle tone. The strong compression of the colon wall generates afferent signals that are below nociceptive threshold in healthy subjects. However, these signals become nociceptive; if the amplitudes of GMCs increase, afferent nerves become hypersensitive, or descending inhibition is impaired. The GMCs also provide the force for rapid propulsion of feces and descending inhibition to relax the internal anal sphincter during defecation. The dysregulation of GMCs is a major factor in colonic motility disorders: irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and diverticular disease (DD). Frequent mass movements by GMCs cause diarrhea in diarrhea predominant IBS, IBD, and DD, while a decrease in the frequency of GMCs causes constipation. The GMCs generate the afferent signals for intermittent short-lived episodes of abdominal cramping in these disorders. Epigenetic dysregulation due to adverse events in early life is one of the major factors in generating the symptoms of IBS in adulthood.

Muscarinic Receptor Subtypes in Smooth Muscle

Muscarinic Receptor Subtypes in Smooth Muscle PDF Author: Richard M. Eglen
Publisher: CRC Press
ISBN: 1000099369
Category : Medical
Languages : en
Pages : 208

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Book Description
This book explores several subtypes of muscarinic receptors that modulate smooth muscle activity. Main topics include a classification of muscarinic receptors, biochemical responses that occur in smooth muscle, the role of muscarinic receptors in the function of gastrointestinal and genitourinary smooth muscle, and prejunctional muscarinic receptors in smooth muscle. Discussions cover the current state of research and are intended to generate further research into the design of novel therapeutics for disorders of smooth muscle function.

Smooth Muscle Excitation

Smooth Muscle Excitation PDF Author: T. B. Bolton
Publisher:
ISBN:
Category : Medical
Languages : en
Pages : 568

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Book Description
This book is a compendium of the latest electrophysiological research on smooth muscles from an international collection of authors. It includes recent discoveries in calcium stores and their relationship to contraction and to electrical changes in the membrane. A major section of the book concentrates on calcium release mechanisms in the cell, their control, and the consequences of calcium release in the cell for membrane events. Smooth Muscle Excitation also covers the effects of chemicals released from adjacent cells. Key Features * State-of-the-art volume that represents a synopsis of all work currently being undertaken in this area throughout the world * Content covers both basic and clinical research * Provides a range of drug development studies * Presents contributions from many internationally recognized smooth muscle physiologists

From Structure to Clinical Development: Allosteric Modulation of G Protein-Coupled Receptors

From Structure to Clinical Development: Allosteric Modulation of G Protein-Coupled Receptors PDF Author:
Publisher: Academic Press
ISBN: 0128201886
Category : Medical
Languages : en
Pages : 330

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Book Description
From Structure to Clinical Development: Allosteric Modulation of G Protein-Coupled Receptors, Volume 88, the latest release in the Advances in Pharmacology series, presents a variety of chapters from the best authors in the field. Chapters in this updated edition include Targeting muscarinic M1 receptor in neurodegeneration, Photo-switchable allosteric ligands, Computational approaches for the design of mGlu receptor allosteric modulators, Allosteric modulation of GLP-1 receptor in metabolic disorders, Group II mGluR roles in the nervous system and their roles in addiction, RAMPs as allosteric modulators of Class B GPCRs, Structure-based discovery and development of mGlu5 NAMs, and much more. - Includes the authority and expertise of leading contributors in pharmacology - Presents the latest release in the Advances in Pharmacology series

Autonomic Failure

Autonomic Failure PDF Author: C. J. Mathias
Publisher: Oxford University Press, USA
ISBN: 9780192628510
Category : Medical
Languages : en
Pages : 562

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Book Description
This fourth edition of Autonomic Failure (now available in paperback) covers the many recent advances made in our understanding of the autonomic nervous system. There are 20 new chapters and extensive revisions of all other contributions. Autonomic failure, fourth edition makes diagnosis increasingly precise by fully evaluating the underlying anatomical and functional deficits, thereby allowing more effective treatment. This new edition continues to provide practitioners from a variety of fields, including neurology, cardiology, geriatric medicine, diabetology, and internal medicine, with a rational guide to aid in the recognition and management of autonomic disorders. The book starts with an updated classification of autonomic disorders and a history of the autonomic nervous system. The first two sections of the book deal with the fundamental aspects of autonomic structure, function, and integration. There are new chapters dealing with neurobiology, nerve growth factors, genetic mutations, neural and hormonal control of the cerebral circulation, innervation of the lung, and pathophysiological mechanisms causing nausea and vomiting. Advances in the clinical management of autonomic disorders are critically dependent on the bridge made between the basic and applied sciences.

The Cholinergic Synapse

The Cholinergic Synapse PDF Author: Victor P. Whittaker
Publisher: Springer Science & Business Media
ISBN: 3642732208
Category : Medical
Languages : en
Pages : 766

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Book Description
One of the most impressive works of scholarship in the field of experimental pharmacology has been the Heffter-Heubner Handbuch der experimentellen Pharmakologie, internationalized some years ago under the title Handbook 0/ Experimental Pharmacology and kept up to date by a series of numbered Ergiin zungswerke or supplementary volumes which have now replaced in importance the original Handbuch. These volumes constitute a valuable and continuously up dated multi author review series of topics important in modern pharmacology and allied sciences. The Editorial Board of the Handbook invited me 2 years ago to undertake, as subeditor, the preparation of a new volume entitled The Cholinergic Synapse. A previous volume in this series, vol. 15, Cholinesterases and Anticholinesterase Agents, edited by GEORGE KOELLE, was published in 1963 and was far wider in scope than its title suggested: it was, in fact an authoritative summing up of the whole subject of cholinergic function and still has some value today as an account of the state of the art as it was at that time. Since then another excellent review, of a specific cholinergic synapse, has appeared in this series: this was vol. 42, Neuromuscular Junction, edited by ELEANOR ZAIMIS and published in 1976. A third volume, vol. 53, Pharmacology o/Ganglionic Transmission, which appeared in 1980 and was edited by D. A. KHARKEVICH, includes important aspects of autonomic cholinergic function.

Functional Neurobiology of Aging

Functional Neurobiology of Aging PDF Author: Patrick R. Hof
Publisher: Elsevier
ISBN: 008052558X
Category : Medical
Languages : en
Pages : 989

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Book Description
Some well-known age-related neurological diseases include Parkinson's disease, Alzheimer's disease, deafness, and blindness. Even more common are the problems of aging which are not due to disease but to more subtle impairments in neurobiological systems, including impairments in vision, memory loss, muscle weakening, and loss of reproductive functions, changes in body weight, and sleeplessness. As the average age of our society increases, diseases of aging continue to become more common, and conditions associated with aging need more attention by doctors and researchers. In 1991, patients over the age of 65 saw their doctors an average of eight times per year. Research funding is provided by the Neuroscience and Neuropsychology of Aging (NNA) Program, which is run by the National Institute on Aging. This book offers a comprehensive overview of all topics related to functional impairments which are related to the aging brain and nervous system. It is organized according to four general functions: movement, senses, memory, and neuroendocrine regulation. Written by the leading researchers in the field, this comprehensive work addresses both impairments associated with diseases and not associated with diseases, making it easier to understand the mechanisms involved. Functional Neurobiology of Aging is an important reference for professionals and students involved in aging research, as well as physicians who need to recognize and understand age-related impairments. - Organized by function, making it easy to find and understand the material - Addresses impairments both associated with diseases and not associated with diseases - Written by leading researchers in the field - Most comprehensive source of information on the neurobiology of aging