The Na, K-ATPase


Book Description

This text addresses the question, How does the sodium pump pump'. A variety of primary structure information is available, and progress has been made in the functional characterization of the Na, K-pump, making the answer to this question possible, within reach of currently used techniques




The Sodium Pump


Book Description

The sodium of animal cell membranes converts the chemical energy obtained from the hydrolysis of adenosine 5' -triphosphate into a movement of the cations Na + and K + against an electrochemical gradient. The gradient is used subse quently as an energy source to drive the uptake of metabolic substrates in polar epithelial cells and to use it for purposes of communications in excitable cells. The biological importance of the sodium pump is evident from the fact that be tween 20-70% of the cell's metabolic energy is consumed for the pumping pro cess. Moreover, the sodium pump is an important biological system involved in regulatory processes like the maintenance of the cells' and organism's water me tabolism. It is therefore understandable that special cellular demands are han dled better by special isoforms of the sodium pump, that the expression of the sodium pump and their isoforms is regulated by hormones as is the activity of the sodium pump via hormone-regulated protein kinases. Additionally, the sodium pump itself seems to be a receptor for a putative new group of hormones, the endogenous digitalis-like substances, which still have to be defined in most cases in their structure. This group of substances has its chemically well known coun terpart in steroids from plant and toad origin which are generally known as "car diac glycosides". They are in medical use since at least 200 years in medicine in the treatment of heart diseases.




Regulation of Membrane Na+-K+ ATPase


Book Description

Na+-K+ ATPase or Na-pump ATPase, a member of “P”-type ATPase superfamily, is characterized by association of multiple isoforms mainly of it’s α- and β- subunits. At present four different α- (α-1,α-2,α-3 and α-4) and three β- (β-1, β-2, and β-3) isoforms have been identified in mammalian cells and their differential expressions are tissue specific. Regulation of Na+-K+ ATPase activity is an important but a complex process, which involves short-term and long-term mechanisms. Short-term regulation of Na+-K+ ATPase is either mediated by changes in intracellular Na+ concentrations that directly affect the Na+-pump activity or by phosphorylation/dephosphorylation-mediated by some stimulants leading to changes in its expression and transport properties. On the other hand, long-term regulation of Na+-K+ ATPase is mediated by hormones, such as mineralocorticoids and thyroid hormones, which cause changes in the transcription of genes of α- and β- subunits leading to an increased expression in the level of Na+-pump. Several studies have revealed a relatively new type of regulation that involves the association of small, single span membrane proteins with this enzyme. These proteins belong to the FXYD family, the members of which share a common signature sequence encompassing the transmembra ne domain adjacent to the isoform(s) of α-β subunits of Na+-K+ ATPase. Considering the extraordinary importance of Na+-K+ ATPase in cellular function, several internationally established investigators have contributed their articles in the monograph entitled “Regulation of Membrane Na+-K+ ATPase” for inspiring young scientists and graduate students to enrich their knowledge on the enzyme, and we are sure that this book will soon be considered as a comprehensive scientific literature in the area of Na+-K+ ATPase regulation in health and disease.




Basic Neurochemistry


Book Description

Basic Neurochemistry, Eighth Edition, is the updated version of the outstanding and comprehensive classic text on neurochemistry. For more than forty years, this text has been the worldwide standard for information on the biochemistry of the nervous system, serving as a resource for postgraduate trainees and teachers in neurology, psychiatry, and basic neuroscience, as well as for medical, graduate, and postgraduate students and instructors in the neurosciences. The text has evolved, as intended, with the science. This new edition continues to cover the basics of neurochemistry as in the earlier editions, along with expanded and additional coverage of new research from intracellular trafficking, stem cells, adult neurogenesis, regeneration, and lipid messengers. It contains expanded coverage of all major neurodegenerative and psychiatric disorders, including the neurochemistry of addiction, pain, and hearing and balance; the neurobiology of learning and memory; sleep; myelin structure, development, and disease; autism; and neuroimmunology. - Completely updated text with new authors and material, and many entirely new chapters - Over 400 fully revised figures in splendid color - 61 chapters covering the range of cellular, molecular and medical neuroscience - Translational science boxes emphasizing the connections between basic and clinical neuroscience - Companion website at http://elsevierdirect.com/companions/9780123749475




The Enzymes of Biological Membranes


Book Description

Much of the information currently available on the transport systems of bacterial and animal cell membranes and their mode of coupling to metabolic supply of energy can be found in this volume. Consideration of the participating enzymes dictated the choice of topics: Several transport systems where little information is available on the enzymology of the process are not included, while separate chapters deal with y-glutamyl transpeptidase and intestinal disaccharidases which meet many of the requirements of transport enzymes. The volume also includes two chapters on photosynthetic membranes as a general introduction to the topic. Other aspects of biological transport and photosynthesis will be developed in detail in a forthcoming volume now in preparation. These chapters reveal the excitement and rapid advance of the field, the daily reports of new concepts, new techniques, and new experimental findings which instantly interact to generate further progress. Our aim was to provide a starting point for those who are just beginning, and an opportunity for others to stop, take stock, and start in a new direction. My warmest thanks to all who contributed to this volume.




Cardiac Glycosides 1785–1985


Book Description

The bicentenary of William Withering's now famous medical report entitled "An Account of the Foxglove and Some of its Medical Uses" has given us the occasion to analyze the state of the art. Cardiac glycosides in 1985 are considered tobe the basis for medical treatment of myocardial failure, together with diuretics and vasodilators in the more severe cases. Nevertheless, the controversy as to their exact place in the treatment of heart failure with sinus rhythm has never ceased. Although cardiac glycosides are of unquestionable value in tachycardia caused by atrial fibrillation or atrial flutter, the chronic use of these drugs in sinus rhythm is not generally accepted. The development of tolerance has been reported. It is of interest that Withering hirnself wrote: "-let it (foxglove) be continued until it either acts on the kidneys, the stomach, the pulse, or the bowels; Iet it be stopped upon the first appearance of any of these effects, and I will maintain that the patient will not suffer from its exhibition, nor the practitioner be disappointed in any reasonable expectation. " In West Germany alone, more than three million patients (about 5% of the total population) are constantly taking cardiac glycosides. These drugs are the most prescribed medicaments in many countries. Thus, we considered it worthwhile and necessary to review in a critical way today's knowledge about the foxglove; to report new findings and to evaluate old Statements.




Electrogenic Ion Pumps


Book Description

Electrogenic ion pumps convert chemical, reduction-oxidation, or light energy- into ion concentration differences across all living cells. They are the engines that run cells. In this text, Dr Lunger develops the principles of physical chemistry required to understand the functions of these macromolecules.




Insulin Action


Book Description

In 1996 the 75th anniversary of the discovery of insulin was celebrated at the University of Toronto, the scene of that discovery in 1921. This volume was stimulated by the scientific program which was staged at that time and brought together much of the world's best talent to discuss and analyze the most recent developments in our understanding of pancreatic function, insulin secretion, the interaction of insulin with its target tissues, the mechanism of insulin action at the cellular level, and the defects which underlie both Type I (insulin-dependent diabetes mellitus, IDDM) and Type II (noninsulin-dependent diabetes mellitus, NIDDM) forms of the disease. We have chosen to focus the present volume on work related to insulin action.




Current Topics in Membranes


Book Description

Current Topics in Membranes




Brain Hypoxia and Ischemia


Book Description

Brain Hypoxia and Ischemia explores the various aspects of cell death and survival that are crucial for understanding the basic mechanisms underlying brain hypoxia and ischemia. Chapters focus on a panorama of issues including the role of ion channels/transporters, mitochondria and apoptotic mechanisms, the roles of glutamate/NMDA, mechanisms in penumbral cells and the importance of intermittent hypoxia and gene regulation under these stressful conditions. The volume explores findings from both mammalian and invertebrate model systems and their applicability to human systems and diseases. Careful consideration is also given to differences in hypoxia and ischemia across development. This volume aims to increase the understanding of these mechanisms and to stimulate research on better diagnosis and treatment of diseases that afflict the brain and potentially other organs when O2 levels are dysregulated. Brain Hypoxia and Ischemia is designed for neuroscientists, clinicians and medical/graduate students for use in both basic research and clinical practice.