Hibernation and the Hypothalamus


Book Description

Mammalian hibernation is commonly thought of as something completely out of the ordinary, a "unique and unorthodox state." The present book takes the opposite view. It argues that the physiological achievements of hibernators do not deEend on special mechanisms but on special use of ordinary mechanisms. It is precisely this that makes the hibernators important. If the hibernators de pend on some unique physiological principle their study is that of a biological curio. But if they are using basic mammalian systems in a quantitatively extreme way, then they are a naturally occurring preparation of enormous potential. Hibernation involves every aspect of the animal's biology from fat metabo lism to behavior, from thermoregulation to dental caries; every system in the body is affected in some way or other by hibernation. A comprehensive account of hibernation would be almost coextensive with an account of the whole of mammalian biology. The present book does not attempt to describe everything that has been discovered about hibernation. Excellent coverage for that already exists in the proceedings of three recent symposia and in the other major source materials listed on page 233. There is in fact an enormous amount of information already available. But there is a difference between information and understanding. Despite the increasing volume of research and growing interest in mammalian hibernation, there is little appreciation of the essential characteristics of the phenomena. The pieces of the puzzle lie scattered.










Hibernation and Torpor in Mammals and Birds


Book Description

Hibernation and Torpor in Mammals and Birds explores the physiological factors that control hibernation and torpor in birds and mammals. This text covers topics ranging from metabolism in hibernation to the role of endocrines, respiration and acid-base state in hibernation, and theories of hibernation. This book is comprised of 14 chapters and begins with an overview of some clear-cut definitions and why mammals and birds hibernate. The reader is then introduced to the variations from euthermia that have been observed among birds and mammals. To give some structure to this listing, the approach is phylogenetic, starting with the birds and proceeding through the primitive to the more advanced mammals. Subsequent chapters explains the process of entering hibernation and the hibernating state, itself; capability of a species in natural hibernation to arouse from that state using self-generated heat; physiological changes at the start of a spontaneous arousal; and physiological mechanisms underlying the ability of hibernators to rewarm. Consideration is also given to intermediary metabolism in hibernation, cold adaptation of metabolism in hibernators, and the response of hibernators to various extrinsic influences such as neoplastic growth, radiation injury, and parasitism and symbionts. This book will be of interest to students and researchers in fields ranging from zoology to physiology and biophysics.
















Neuroprotection in the Hibernating Brain


Book Description

"Hibernation, a natural model of tolerance to 'cerebral ischemia', represents a state of pronounced fluctuation in cerebral blood flow where no brain damage occurs. This study systematically investigates the brain tissue response of hibernating and euthermic arctic ground squirrels to CNS trauma, modeled by insertion of microdialysis probes. The effect of glutamate, an excitatory amino acid neurotransmitter, on the cellular response and the origin of the significant amount of gltuamate were determined by quantitative microdialysis study. The present results indicate in euthermic brain tissue a typical inflammatory tissue response evidenced by the presence of activated microglia and astrocytes and the oxidative stress response. However, this response was profoundly suppressed in hibernating animals. Importantly, the progressive increase in [glu]dia is not necessarily associated with the enhanced tissue response observed in euthermic animals and could be avoided by using sterile microdialysis technique, which suggests a microbial origin of glutamate"--Leaf iii.




The Orexin System. Basic Science and Role in Sleep Pathology


Book Description

The orexin system, discovered in 1998, has emerged as a crucial player in regulating the sleep and wake balance inside our brain. This discovery has sparked a burst of novel and dynamic research on the physiology and pathology of sleep. The Orexin System: Basic Science and Role in Sleep Pathology honors this research and the authors share their ideas and perspectives on the novel developments within the field. The book examines the intricate role of the orexin system in regulating sleep and wake, and its interaction with other wake-regulating systems. The orexin system is dissected at the cellular and molecular level to explore the diversity of the orexin-producing neurons, their projections, and their signaling pathways. Additionally, the book discusses the diseases which are associated with a dysfunctional orexin system, such as narcolepsy, insomnia, substance abuse, and Alzheimer’s disease, and explores the new potential therapeutic applications derived from the burst of research around this fascinating system. This publication is essential reading for neurobiologists, neurologists, psychopharmacologists, sleep researchers, and other researchers and clinical scientists interested in sleep, sleep research, insomnia, and medicine in general.