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Inhibitory Function in Auditory Processing

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196678 Year: Pages: 231 DOI: 10.3389/978-2-88919-667-8 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Neurology
Added to DOAB on : 2016-08-16 10:34:25
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There seems little doubt that from the earliest evolutionary beginnings, inhibition has been a fundamental feature of neuronal circuits - even the simplest life forms sense and interact with their environment, orienting or approaching positive stimuli while avoiding aversive stimuli. This requires internal signals that both drive and suppress behavior. Traditional descriptions of inhibition sometimes limit its role to the suppression of action potential generation. This view fails to capture the vast breadth of inhibitory function now known to exist in neural circuits. A modern perspective on inhibitory signaling comprises a multitude of mechanisms. For example, inhibition can act via a shunting mechanism to speed the membrane time constant and reduce synaptic integration time. It can act via G-protein coupled receptors to initiate second messenger cascades that influence synaptic strength. Inhibition contributes to rhythm generation and can even activate ion channels that mediate inward currents to drive action potential generation. Inhibition also appears to play a role in shaping the properties of neural circuitry over longer time scales. Experience-dependent synaptic plasticity in developing and mature neural circuits underlies behavioral memory and has been intensively studied over the past decade. At excitatory synapses, adjustments of synaptic efficacy are regulated predominantly by changes in the number and function of postsynaptic glutamate receptors. There is, however, increasing evidence for inhibitory modulation of target neuron excitability playing key roles in experience-dependent plasticity. One reason for our limited knowledge about plasticity at inhibitory synapses is that in most circuits, neurons receive convergent inputs from disparate sources. This problem can be overcome by investigating inhibitory circuits in a system with well-defined inhibitory nuclei and projections, each with a known computational function. Compared to other sensory systems, the auditory system has evolved a large number of subthalamic nuclei each devoted to processing distinct features of sound stimuli. This information once extracted is then re-assembled to form the percept the acoustic world around us. The well-understood function of many of these auditory nuclei has enhanced our understanding of inhibition's role in shaping their responses from easily distinguished inhibitory inputs. In particular, neurons devoted to processing the location of sound sources receive a complement of discrete inputs for which in vivo activity and function are well understood. Investigation of these areas has led to significant advances in understanding the development, physiology, and mechanistic underpinnings of inhibition that apply broadly to neuroscience. In this series of papers, we provide an authoritative resource for those interested in exploring the variety of inhibitory circuits and their function in auditory processing. We present original research and focused reviews touching on development, plasticity, anatomy, and evolution of inhibitory circuitry. We hope our readers will find these papers valuable and inspirational to their own research endeavors.

Untersuchung der Wechselwirkung von NO und Ruß in laminaren, rußenden Vormischflammen

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ISBN: 9783731503309 Year: Pages: VI, 173 p. DOI: 10.5445/KSP/1000045122 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:01:59
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Emission limits are being steadily tightened. This requires an ever increasing reduction of combustion generated pollutants. This book focuses on soot and NO and their heterogeneous interactions. With the help of laser spectroscopic methods and mathematical modeling of flames, a heterogeneous reaction mechanism for surface reactions can be validated and a significant influence on precursor reactions of soot formation can be shown.

Extracellular Nucleotides in the Regulation of Kidney Functions

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889195046 Year: Pages: 77 DOI: 10.3389/978-2-88919-504-6 Language: English
Publisher: Frontiers Media SA
Subject: Physiology --- Science (General)
Added to DOAB on : 2015-12-03 13:02:24
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ATP is normally regarded as the major source of fuel for the energy-demanding processes within cells; however, ATP and other nucleotides (such as ADP, UTP, UDP) can be released from cells, where they act as autocrine or paracrine signaling molecules to affect cellular and tissue functions. In response to various stimuli, ATP and other nucleotides are released from cells in a regulated fashion, either by exocytosis of nucleotide-containing vesicles, or through channels in the plasma membrane. This process occurs in virtually every organ or cell in the body. The cellular effects of these extracellular nucleotides are mediated through specific membrane receptors (P2X and P2Y). These nucleotide signals can be terminated by rapid degradation of the ligand molecules by ecto-nucleotidases (e.g., NTPDases and NPPs). Many of the molecular components essential to nucleotide signaling have been cloned and characterized in detail, and their crystal structures are beginning to emerge. The collected data on extracellular nucleotides suggest a vivid and dynamic signaling system that is modulated by the expression and sensitivity of specific receptors on cells, and by the regulated release and extracellular degradation of ATP and other nucleotides; thus creating a microenvironment of highly regulated paracrine or autocrine control mechanisms. Within the kidney, extracellular nucleotides have emerged as potent modulators of glomerular, tubular, and microvascular functions. These functions include, but are not limited to, tubular transport of water and sodium, tubuloglomerular feedback and auto-regulation, regulation of blood pressure and the microcirculation, oxidative stress, and cell proliferation/ necrosis/apoptosis. Moreover, studies have also uncovered the interaction of nucleotide signaling with other mediators of renal function, such as vasopressin, aldosterone, nitric oxide, prostaglandins, angiotensin II, and the ATP-break down product adenosine. These insights have provided a more comprehensive and cohesive picture of the role of extracellular nucleotides in the regulation of renal function in health and disease. The availability of transgenic mouse models of the key proteins involved in nucleotide signaling has markedly enhanced our understanding of the physiological and pathophysiological roles of the different components of the system in the kidney. Although at a preliminary stage, the pathophysiological significance of this system in the kidney holds the key for the development of an entirely new class of drugs for the treatment of disease conditions, including disorders of water and/or sodium homeostasis, hypertension, acute kidney injury, etc. Thus, the regulation of renal function by extracellular nucleotides is clearly emerging as a distinct field and discipline in renal physiology and pathophysiology that has the potential to develop new drug treatments. In this e-book, we bring together a spectrum of excellent papers by leading experts in the field which present and discuss the latest developments and state-of-the-art technologies.Last but not least, we thank all the authors for contributing their valuable work and the Frontiers in Physiology Editorial Office for bringing out this e-book.

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