Histaminergic Neurons

This book provides an overview on the histaminergic neuron system in the brain for neuroscience, anatomy, pharmacology, biochemistry, and medical researchers. Topics discussed include the biochemistry of enzymes; histamine receptors (H1, H2, and H3); morphology, coexistance, and development of the histaminergic neuron system; electrophysiological studies on vertebrate and invertebrate neurons; as well as the functions of the histamine neurons.

Brain aminergic pathways are organized in parallel and interacting systems, which support a range of functions, from homoeostatic regulations to cognitive, and motivational processes. Despite overlapping functional influences, dopamine, serotonin, noradrenaline and histamine systems provide different contributions to these processes. The histaminergic system, long ignored as a major regulator of the sleep-wake cycle, has now been fully acknowledged also as a major coordinator of attention, learning and memory, decision making. Although histaminergic neurons project widely to the whole brain, they are functionally heterogeneous, a feature which may provide the substrate for differential regulation, in a region-specific manner, of other neurotransmitter systems. Neurochemical preclinical studies have clearly shown that histamine interacts and modulates the release of neurotransmitters that are recognized as major modulators of cognitive processing and motivated behaviours. As a consequence, the histamine system has been proposed as a therapeutic target to treat sleep-wake disorders and cognitive dysfunctions that accompany neurodegenerative and neuroinflammatory pathologies. Last decades have witnessed an unexpected explosion of interest in brain histamine system, as new receptors have been discovered and selective ligands synthesised. Nevertheless, the complete picture of the histamine systems fine-tuning and its orchestration with other pathways remains rather elusive. This Research Topic is intended to offer an inter-disciplinary forum that will improve our current understanding of the role of brain histamine and provide the fundamentals necessary to drive innovation in clinical practice and to improve the management and treatment of neurological disorders.

A comprehensive and detailed overview of the current state of preclinical research on histamine and histamine receptors. Part of the book focuses on novel approaches to the study of histamine receptors such as polymorphism, genetic linkage, and computational analysis, and on the use of new histaminergic ligands in diseases such as asthma and dermatitis. Several chapters will be devoted to the role of histamine in the control of homeostatic and behavioral responses such as the sleep-wake cycle, regulation of the blood brain barrier, food intake, alertness, itch, and memory formation and consolidation.

Research in the field of histamine receptors over the past 100 years went hand-in-hand with the development of modern pharmacology. Advances in histamine research led by outstanding scientists was so incisive that the clinical approach to treat allergies and gastrointestinal ailments was revolutionized. The pharmacological treatment of peptic ulcer and gastroesophageal reflux was indeed a revolution, as it ended the surgical intervention. Interest in histamine pharmacology was resurrected by the discovery of another histamine receptor, number 4, using genomics-based reverse pharmacological approaches for screening orphan GPCRs. This receptor is preferentially expressed by immune cells and its discovery raised hopes for its translational exploitation as a new therapeutic target for unmet medical needs ranging from asthma to cancer. However, several drawbacks emerged and dramatically slowed down research in the field. A better understanding of receptor intra-and interspecies heterogeneity will certainly improve and accelerate the translation of experimental data into clinical practice. Also, the plethora of data on brain histamine is hinting at a fundamental role of this system as a hub that receives internal and peripheral stimuli to allocate the necessary excitation to specific brain circuits that preside the appropriate behavioral responses. The development of new histaminergic ligands is an ongoing process that constantly provide new preclinical tools. The aim of this book is to cover the most important aspects of histamine receptor function and pharmacology in the central nervous system and to provide a comprehensive overview of the preclinical and clinical advances made in recent decades and the exciting prospects for the future. It highlights the clinical areas where there is a great need for new therapeutic approaches and where novel histaminergic agents may be useful for personalized medicine.

Reveals an Emerging Avenue of Potential Treatments for a Host of Challenging Diseases and Disorders The H3 receptor is known to play a major role in a range of CNS disorders, including those affecting cognitive functions such as ADHD and Alzheimer’s disease, as well as sleep disorders, obesity, epilepsy, schizophrenia, depression, and neurodegeneration. In light of dramatic advances in research at the molecular level, supported by impressive clinical studies, optimism remains high that an H3 receptor-related drug could hit the market soon. The Third Histamine Receptor: Selective Ligands as Potential Therapeutic Agents in CNS Disorders provides a thorough grounding in advances made over the last two decades. It brings together an elite group of 30 pioneering researchers. In writing about their own work, these scientists report on the cutting-edge investigations that are now being conducted across a variety of disciplines. This text is designed to aid researchers and inform those involved in the treatment and clinical aspects of a number of histamine-related diseases. Presents Several Disease-Specific Chapters Certainly, the most comprehensive and cutting-edge volume in the field, this text includes material drawn from groundbreaking research techniques and patent literature. Put together with great thought and passion, it is written to serve as a primary resource for anyone involved with or interested in the identification and localization of H3 receptors and the ligands being developed as therapeutic agents to treat a wide range of diseases including some that were once considered intractable.

In the early eighties when the H3 receptor was identified, many thought that an H3 ligand, an agonist or an antagonist, would become available as a therapeutic agent. This has not occurred. The reason for this could be the fact that many investigators consider histamine mainly, if not only, as a mediator present in for example mast cells being released during allergic events. However, it has become apparent that histamine is an important neurotransmitter. Its role in the nervous system, especially in the central part of it, is rather extensive. The H3 receptor is mainly found as a presynaptic one, both on histaminergic neurons (the auto-type) and on other neuronal systems (the hetero-type). Both the H3 agonist and the H3 antagonist cause important pharmacological effects. Several ligands have become available now, including radiolabelled analogues. In this book, the current state of affairs with regards to the medicinal chemistry and pharmacology of the H3 receptor and the several ligands available are presented by a number of experts in the field. The book presents an extended review of what has happened since the first H3 paper appeared. The editors hope that publication of this work will lead to an increase in interest of both academia and industry for the H3 receptor, especially as a target for drug development.

Basic Neurochemistry: Molecular, Cellular and Medical Aspects, a comprehensive text on neurochemistry, is now updated and revised in its Seventh Edition. This well-established text has been recognized worldwide as a resource for postgraduate trainees and teachers in neurology, psychiatry, and basic neuroscience, as well as for graduate and postgraduate students and instructors in the neurosciences. It is an excellent source of information on basic biochemical processes in brain function and disease for qualifying examinations and continuing medical education. Completely updated with 60% new authors and material, and entirely new chapters Over 400 fully revised figures in splendid color