Purinergic Signalling and the Nervous System


Book Description

In the first 20 years that followed the purinergic signalling hypothesis in 1972, most scientists were sceptical about its validity, largely because ATP was so well established as an intracellular molecule involved in cell biochemistry and it seemed unlikely that such a ubiquitous molecule would act as an extracellular signalling molecule. However, after the receptors for ATP and adenosine were cloned and characterized in the early 1990s and ATP was established as a synaptic transmitter in the brain and sympathetic ganglia, the tide turned. More recently it has become clear that ATP is involved in long-term (trophic) signalling in cell proliferation, differentiation and death, in development and regeneration, as well as in short-term signalling in neurotransmission and secretion. Also, important papers have been published showing the molecular structure of P2X receptors in primitive animals like Amoeba and Schistosoma, as well as green algae. This has led to the recognition of the widespread nature of the purinergic signalling system in most cell types and to a rapid expansion of the field, including studies of the pathophysiology as well as physiology and exploration of the therapeutic potential of purinergic agents. In two books, Geoffrey Burnstock and Alexej Verkhratsky have aimed at drawing together the massive and diverse body of literature on purinergic signalling. The topic of this first book is purinergic signalling in the peripheral and central nervous systems and in the individual senses. In a second book the authors focus on purinergic signalling in non-excitable cells, including those of the airways, kidney, pancreas, endocrine glands and blood vessels. Diseases related to these systems are also considered.




Glioma Signaling


Book Description

Gliomas, developing in the brain from the transformed glial cells, are a very special kind of tumor, extremely refractory to conventional treatments. Therefore, for the development of new antitumor strategies, a better understanding of molecular mechanisms responsible for their biology, growth and invasion is still needed. This book is a reference on cellular signaling processes regulating gliomas physiology and invasiveness. The work is focused on the mechanism of nucleotide receptor activation by exogenous nucleotides and formation of complex signaling cascades induced by growth factors, cytokines and cannabinoids. The second edition of the book enriched in new chapters provides a framework explaining how signal transduction elements may modulate numerous genetic and epigenetic alterations, describes the role of local microenvironment in cellular growth, progression and invasion and, in the light of extensive new results, presents perspectives concerning potential targets for gliomas therapy.




Purinergic Signalling in Neuron-Glia Interactions


Book Description

ATP, the intracellular energy source, is also an extremely important cell–cell signalling molecule for a wide variety of cells across evolutionarily diverse organisms. The extracellular biochemistry of ATP and its derivatives is complex, and the multiple membrane receptors that it activates are linked to many intracellular signalling systems. Purinergic signalling affects a diverse range of cellular phenomena, including ion channel function, cytoskeletal dynamics, gene expression, secretion, cell proliferation, differentiation and cell death. Recently, this class of signalling molecules and receptors has been found to mediate communication between neurons and non-neuronal cells (glia) in the central and peripheral nervous systems. Glia are critical for normal brain function, development and response to injury. Neural impulse activity is detected by glia and purinergic signalling is emerging as a major means of integrating functional activity between neurons, glia and vascular cells in the nervous system. These interactions mediate effects of neural activity on the development of the nervous system and in association with injury, neurodegeneration, myelination and cancer. Bringing together contributions from experts in diverse fields, including glial biologists, neurobiologists and specialists in purinergic receptor structure and pharmacology, this book considers how extracellular ATP acts to integrate communication between different types of glia, and between neurons and glia. Beginning with an overview of glia and purinergic signalling, it contains detailed coverage of purine release, receptors and reagents, purinergic signalling in the neural control of glial development, glial involvement in information processing, and discussion of the interactions between neurons and microglia.




Adenosine Receptors in Health and Disease


Book Description

Since their discovery approximately 25 years ago, adenosine receptors have now emerged as important novel molecular targets in disease and drug discovery. These proteins play important roles in the entire spectrum of disease from inflammation to immune suppression. Because of their expression on a number of different cell types and in a number of different organ systems they play important roles in specific diseases, including asthma, rheumatoid arthritis, Parkinson’s disease, multiple sclerosis, Alzheimer’s disease, heart disease, stroke, cancer, sepsis, and obesity. As a result of intense investigations into understanding the molecular structures and pharmacology of these proteins, new molecules have been synthesized that have high specificity for these proteins and are now entering clinical trials. These molecules will define the next new classes of drugs for a number of diseases with unmet medical needs.




The Physiology of the Lower Urinary Tract


Book Description

In this book we attempt a synthesis of knowledge from two investigative extremes. On the one hand, neurophysiology and neuropharmacology are progressing via the single neuron to a subcellular level; on the other, clinicians are studying the function ofthe human urinary system in vivo as a whole. A special effort must be made over the next decade to bridge this gap. We hope that the information summarized here will catalyse the process. In 1968, de Groat and Ryall published a group of papers in the Journal of Physiology in which modern quantitative electrophysiological techniques were applied to the study ofthe reflexes that regulate bladder Junction. These papers represent alandmark in the history of bladder neurophysiology, forming a dividing li ne between old and new. The earlier techniques of lesioning and stimulation of nervous structures yielded mainly qualitative information which was open to criticism because of lack of precise control over what was actually being destroyed or stimulated. Much of this earlier work was reviewed in an authoritative volume by Bors and Comarr in 1971, entitled Neurolqgical Urology. The 16 years have seen great advances in our understanding ofthe control oflower subsequent urinary tract function.







Receptors P1 and P2 as Targets for Drug Therapy in Humans


Book Description

This book aims to provide a brief update on the functions of purinergic receptors in various systems, in addition to the signaling pathway activated to mediate these functions. We address the influence of hypoxia by modulating the activity of these receptors under physiological and pathophysiological conditions. Additionally, we describe the mechanisms of induction of pain and inflammation in different systems. Finally, the book discusses some of the main bioinformatics tools currently used to improve or discover new prototypes capable of selectively acting on these receptors with estimated parameters of satisfactory solubility and toxicity for possible commercial implementation.




Enteric Glia


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




Glial Physiology and Pathophysiology


Book Description

Glial Physiology and Pathophysiology provides a comprehensive, advanced text on the biology and pathology of glial cells. Coverae includes: the morphology and interrelationships between glial cells and neurones in different parts of the nervous systems the cellular physiology of the different kinds of glial cells the mechanisms of intra- and inter-cellular signalling in glial networks the mechanisms of glial-neuronal communications the role of glial cells in synaptic plasticity, neuronal survival and development of nervous system the cellular and molecular mechanisms of metabolic neuronal-glial interactions the role of glia in nervous system pathology, including pathology of glial cells and associated diseases - for example, multiple sclerosis, Alzheimer's, Alexander disease and Parkinson's Neuroglia oversee the birth and development of neurones, the establishment of interneuronal connections (the 'connectome'), the maintenance and removal of these inter-neuronal connections, writing of the nervous system components, adult neurogenesis, the energetics of nervous tissue, metabolism of neurotransmitters, regulation of ion composition of the interstitial space and many, many more homeostatic functions. This book primes the reader towards the notion that nervous tissue is not divided into more important and less important cells. The nervous tissue functions because of the coherent and concerted action of many different cell types, each contributing to an ultimate output. This reaches its zenith in humans, with the creation of thoughts, underlying acquisition of knowledge, its analysis and synthesis, and contemplating the Universe and our place in it. An up-to-date and fully referenced text on the most numerous cells in the human brain Detailed coverage of the morphology and interrelationships between glial cells and neurones in different parts of the nervous system Describes the role og glial cells in neuropathology Focus boxes highlight key points and summarise important facts Companion website with downloadable figures and slides




Neural Control of Renal Function


Book Description

The kidney is innervated with efferent sympathetic nerve fibers reaching the renal vasculature, the tubules, the juxtaglomerular granular cells, and the renal pelvic wall. The renal sensory nerves are mainly found in the renal pelvic wall. Increases in efferent renal sympathetic nerve activity reduce renal blood flow and urinary sodium excretion by activation of α1-adrenoceptors and increase renin secretion rate by activation of β1-adrenoceptors. In response to normal physiological stimulation, changes in efferent renal sympathetic nerve activity contribute importantly to homeostatic regulation of sodium and water balance. The renal mechanosensory nerves are activated by stretch of the renal pelvic tissue produced by increases in renal pelvic tissue of a magnitude that may occur during increased urine flow rate. Activation of the sensory nerves elicits an inhibitory renorenal reflex response consisting of decreases in efferent renal sympathetic nerve activity leading to natriuresis. Increasing efferent sympathetic nerve activity increases afferent renal nerve activity which, in turn, decreases efferent renal sympathetic nerve activity by activation of the renorenal reflexes. Thus, activation of the afferent renal nerves buffers changes in efferent renal sympathetic nerve activity in the overall goal of maintaining sodium balance. In pathological conditions of sodium retention, impairment of the inhibitory renorenal reflexes contributes to an inappropriately increased efferent renal sympathetic nerve activity in the presence of sodium retention. In states of renal disease or injury, there is a shift from inhibitory to excitatory reflexes originating in the kidney. Studies in essential hypertensive patients have shown that renal denervation results in long-term reduction in arterial pressure, suggesting an important role for the efferent and afferent renal nerves in hypertension. Table of Contents: Part I: Efferent Renal Sympathetic Nerves / Introduction / Neuroanatomy / Neural Control of Renal Hemodynamics / Neural Control of Renal Tubular Function / Neural Control of Renin Secretion Rate / Part II: Afferent Renal Sensory Nerves / Introduction / Neuroanatomy / Renorenal Reflexes / Mechanisms Involved in the Activation of Afferent Renal Sensory Nerves / Part III: Pathophysiological States / Efferent Renal Sympathetic Nerves / Afferent Renal Sensory Nerves / Conclusions / References