Endogenous and Exogenous Molecules Modulating Voltage-Gated Potassium Channels PDF Download
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Author: Damon Frampton
Publisher: Linköping University Electronic Press
ISBN: 9180757529
Category :
Languages : en
Pages : 145
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Book Description
The superfamily of voltage-gated potassium (KV) channels is crucial for the normal function of several tissues and represents an attractive pharmacological target for treating disorders such as epilepsy and cardiac arrhythmias. However, any drug designed to target a KV channel must be capable of discriminating between different members within the superfamily, lest they plague the user with deleterious side effects. Such rational design requires structural and functional insight into how the selectivity of a molecule can be tailored to suit the intended target. This thesis combines the use of electrophysiological and computational techniques to investigate the molecular basis for how the function of hKV7 and hERG channels can be modulated by different lipophilic compounds with known or suspected effects on ion channels. These include polyunsaturated fatty acids (PUFAs), cannabidiol (CBD), and synthetic cannabinoid receptor agonists (SCRAs). Using the two-electrode voltage clamp technique on Xenopus oocytes, we find that both PUFAs and CBD modulate the function of hKV7 channels in subtype-specific manners. PUFAs facilitated the activation of hKV7 channels, except for hKV7.4 channels which were instead inhibited. Molecular dynamics simulations revealed that structural differences in the voltage-sensing domain of hKV7.4 conferred a unique, inhibitory PUFA interaction site absent in the other hKV7 subtypes. Once this site was neutralised by mutagenesis, PUFAs facilitated hKV7.4 activation. In the case of CBD, we observed three different responses: inhibition of channels with hKV7.1 subunits, potentiated voltage-sensitivity of channels with hKV7.2 or hKV7.3 subunits and enhanced maximum conductance of channels with hKV7.4 or hKV7.5 subunits. However, these responses were evoked from the same interaction site in the pore domain, indicating a more complex subtype-specific mechanism of action. Finally, using an automated patch-clamp system we screened 36 different SCRAs on the cardiac channels responsible for repolarisation: hERG and hKV7.1/KCNE1. We find 28 of the SCRAs to be inhibitors of hERG and 22 to be inhibitors of hKV7.1/KCNE1. Molecular dynamics simulations suggest the increased susceptibility of hERG to SCRA-mediated inhibition may be due to a unique central cavity site that is absent from the pore domain of hKV7.1/KCNE1. In conclusion, structurally diverse lipophilic molecules of endogenous and exogenous origins can interact with KV channels and influence their function by enhancing or interfering with functional domains. In some instances, structural differences in the channel protein can explain the discrepancies in pharmacology. These findings have implications for both pharmacology (informing rational drug design) and toxicology (identifying targets through which adverse effects may occur).
Author: Damon Frampton
Publisher: Linköping University Electronic Press
ISBN: 9180757529
Category :
Languages : en
Pages : 145
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Book Description
The superfamily of voltage-gated potassium (KV) channels is crucial for the normal function of several tissues and represents an attractive pharmacological target for treating disorders such as epilepsy and cardiac arrhythmias. However, any drug designed to target a KV channel must be capable of discriminating between different members within the superfamily, lest they plague the user with deleterious side effects. Such rational design requires structural and functional insight into how the selectivity of a molecule can be tailored to suit the intended target. This thesis combines the use of electrophysiological and computational techniques to investigate the molecular basis for how the function of hKV7 and hERG channels can be modulated by different lipophilic compounds with known or suspected effects on ion channels. These include polyunsaturated fatty acids (PUFAs), cannabidiol (CBD), and synthetic cannabinoid receptor agonists (SCRAs). Using the two-electrode voltage clamp technique on Xenopus oocytes, we find that both PUFAs and CBD modulate the function of hKV7 channels in subtype-specific manners. PUFAs facilitated the activation of hKV7 channels, except for hKV7.4 channels which were instead inhibited. Molecular dynamics simulations revealed that structural differences in the voltage-sensing domain of hKV7.4 conferred a unique, inhibitory PUFA interaction site absent in the other hKV7 subtypes. Once this site was neutralised by mutagenesis, PUFAs facilitated hKV7.4 activation. In the case of CBD, we observed three different responses: inhibition of channels with hKV7.1 subunits, potentiated voltage-sensitivity of channels with hKV7.2 or hKV7.3 subunits and enhanced maximum conductance of channels with hKV7.4 or hKV7.5 subunits. However, these responses were evoked from the same interaction site in the pore domain, indicating a more complex subtype-specific mechanism of action. Finally, using an automated patch-clamp system we screened 36 different SCRAs on the cardiac channels responsible for repolarisation: hERG and hKV7.1/KCNE1. We find 28 of the SCRAs to be inhibitors of hERG and 22 to be inhibitors of hKV7.1/KCNE1. Molecular dynamics simulations suggest the increased susceptibility of hERG to SCRA-mediated inhibition may be due to a unique central cavity site that is absent from the pore domain of hKV7.1/KCNE1. In conclusion, structurally diverse lipophilic molecules of endogenous and exogenous origins can interact with KV channels and influence their function by enhancing or interfering with functional domains. In some instances, structural differences in the channel protein can explain the discrepancies in pharmacology. These findings have implications for both pharmacology (informing rational drug design) and toxicology (identifying targets through which adverse effects may occur).
Author: Peter C. Ruben
Publisher: Springer Science & Business Media
ISBN: 3642415881
Category : Medical
Languages : en
Pages : 328
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Book Description
A number of techniques to study ion channels have been developed since the electrical basis of excitability was first discovered. Ion channel biophysicists have at their disposal a rich and ever-growing array of instruments and reagents to explore the biophysical and structural basis of sodium channel behavior. Armed with these tools, researchers have made increasingly dramatic discoveries about sodium channels, culminating most recently in crystal structures of voltage-gated sodium channels from bacteria. These structures, along with those from other channels, give unprecedented insight into the structural basis of sodium channel function. This volume of the Handbook of Experimental Pharmacology will explore sodium channels from the perspectives of their biophysical behavior, their structure, the drugs and toxins with which they are known to interact, acquired and inherited diseases that affect sodium channels and the techniques with which their biophysical and structural properties are studied.
Author: Ismail Laher
Publisher: Springer
ISBN: 9783642300172
Category : Medical
Languages : en
Pages : 0
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Book Description
The focus of this collection of illustrated reviews is to discuss the systems biology of free radicals and anti-oxidants. Free radical induced cellular damage in a variety of tissues and organs is reviewed, with detailed discussion of molecular and cellular mechanisms. The collection is aimed at those new to the field, as well as clinicians and scientists with long standing interests in free radical biology. A feature of this collection is that the material also brings insights into various diseases where free radicals are thought to play a role. There is extensive discussion of the success and limitations of the use of antioxidants in several clinical settings.
Author: Richard W. Tsien
Publisher:
ISBN:
Category : Calcium
Languages : en
Pages : 420
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Book Description
Author: Bernat Soria
Publisher:
ISBN:
Category : Medical
Languages : en
Pages : 498
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Book Description
The improved understanding of ion channel structure, achieved through the use of molecular biology techniques, has opened the way for the development of new drugs targeted at specific types of ion channels. This book provides a comprehensive, single-volume overview of the effects of different drugs and toxins on ionic channels. The first part of the book deals with the development of ion channels, while subsequent chapters detail the electrophysiological properties and pharmacology of eight different types of ion channels, including intracellular, cyclic nucleotide-gated, and receptor operated channels. Drug effects in various cell types, along with the potential use of channels in therapeutics, are discussed for each channel type. Comprehensive and up-to-date, Ion Channel Pharmacology is an essential reference for every investigator in this fast-growing area of research.
Author: Mario Diaz
Publisher: Frontiers Media SA
ISBN: 2889457559
Category :
Languages : en
Pages : 135
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Book Description
Author: Colin R Martin
Publisher: Elsevier
ISBN: 0323901409
Category : Medical
Languages : en
Pages : 672
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Book Description
Cannabis Use, Neurobiology, Psychology, and Treatment offers readers a comprehensive reference on neurological changes, both transient and long-term, and other factors surrounding the use of these compounds and extracts. With coverage of both natural and synthetic cannabinoids, this broad coverage allows readers to learn about both adverse and non-adverse effects, including reactivity to pain, changes in behavior, and neuroactivity. This volume provides a platform for research on the effects of these compounds in brain function and neurological dysfunction. Extracts from the Cannabis sativa plant contain scores of psychoactive compounds in addition to the principal agent tetrahydrocannabinol, many of which are neuroactive. - Summarizes cannabis and cannabinoid research in relation to neurological function - Contains chapter abstracts, key facts, a dictionary and a summary - Covers the neuroactivity of multiple Cannabis compounds beyond tetrahydrocannabinol - Includes conditions like depression, anxiety, Parkinson's, psychosis, and epilepsy - Discusses brain structure and brain development, including functional connectivity
Author: Boris V. Krylov
Publisher: Bentham Science Publishers
ISBN: 1608059308
Category : Science
Languages : en
Pages : 211
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Book Description
The monograph is a summary of methods used to study pain receptors and the results obtained in some experiments designed to study the effect of non-opioid analgesics. The molecular mechanisms of nociceptive information control in primary sensory nociceptive neurons are described based on investigations of the membrane signaling cascade (opioid-like receptor → Na+,K+-ATPase → NaV1.8 channel) observed by the authors. Based on this data, the authors conclude that the modulation of NaV1.8 channels responsible for the coding of noxious signals can be carried out due to two novel targeting mechanisms. The first of these is the activation of opioid-like receptors; the second is the activation of Na+/K+-ATPase as a signal transducer. The development of a novel class of analgesics that trigger these mechanisms should lead to a successful solution to the problem of chronic pain relief. Chapters of the monograph cover the general methods used in studying nociceptive pain (including the patch-clamp method), and the mechanism behind the binding of different ligands to these receptors such gamma-pyrones, gamma-pyridines and cardiotonic steroids. This monograph is a valuable reference for neuroscientists, pharmacologists and allied researchers studying pain receptors for the development of safe and effective analgesics.
Author: Thomas Andrew Jepps
Publisher: Frontiers Media SA
ISBN: 2889669149
Category : Science
Languages : en
Pages : 239
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Book Description
This Research Topic was in partnership with CAP Partner for the International Kv7 Channels Symposium held in Naples, Italy on September 2019.
Author: Michel Félétou
Publisher: Morgan & Claypool Publishers
ISBN: 1615041230
Category : Science
Languages : en
Pages : 309
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Book Description
The endothelium, a monolayer of endothelial cells, constitutes the inner cellular lining of the blood vessels (arteries, veins and capillaries) and the lymphatic system, and therefore is in direct contact with the blood/lymph and the circulating cells. The endothelium is a major player in the control of blood fluidity, platelet aggregation and vascular tone, a major actor in the regulation of immunology, inflammation and angiogenesis, and an important metabolizing and an endocrine organ. Endothelial cells controls vascular tone, and thereby blood flow, by synthesizing and releasing relaxing and contracting factors such as nitric oxide, metabolites of arachidonic acid via the cyclooxygenases, lipoxygenases and cytochrome P450 pathways, various peptides (endothelin, urotensin, CNP, adrenomedullin, etc.), adenosine, purines, reactive oxygen species and so on. Additionally, endothelial ectoenzymes are required steps in the generation of vasoactive hormones such as angiotensin II. An endothelial dysfunction linked to an imbalance in the synthesis and/or the release of these various endothelial factors may explain the initiation of cardiovascular pathologies (from hypertension to atherosclerosis) or their development and perpetuation. Table of Contents: Introduction / Multiple Functions of the Endothelial Cells / Calcium Signaling in Vascular Cells and Cell-to-Cell Communications / Endothelium-Dependent Regulation of Vascular Tone / Conclusion / References
