Vascular Innervation And Receptor Mechanisms

Vascular Innervation and Receptor Mechanisms: New Perspectives reviews the areas of structure, function, and pathophysiology of the circulatory system. The text focuses on the role of neuropeptides and structural function of endothelium. The book begins with a brief discussion on the background of autonomic and sensory nerves in the circulatory system, which is provided in Chapter 1. Having established the basic studies in the circulatory system, the book moves to the discussion on the analysis of peptidergic innervations and peptides in vascular control in various disorders. The last part of the book features the clinical applications of neuropeptides, perivascular peptides, and vasoactive peptides in different diseases and regulation, such as cardiovascular regulation, hypertension, congestive heart failure, and migraine and cluster headache. The text will be a good reference to both students and professionals in the fields of biology, chemistry, and medicine.

This e-book will review special features of the cerebral circulation and how they contribute to the physiology of the brain. It describes structural and functional properties of the cerebral circulation that are unique to the brain, an organ with high metabolic demands and the need for tight water and ion homeostasis. Autoregulation is pronounced in the brain, with myogenic, metabolic and neurogenic mechanisms contributing to maintain relatively constant blood flow during both increases and decreases in pressure. In addition, unlike peripheral organs where the majority of vascular resistance resides in small arteries and arterioles, large extracranial and intracranial arteries contribute significantly to vascular resistance in the brain. The prominent role of large arteries in cerebrovascular resistance helps maintain blood flow and protect downstream vessels during changes in perfusion pressure. The cerebral endothelium is also unique in that its barrier properties are in some way more like epithelium than endothelium in the periphery. The cerebral endothelium, known as the blood-brain barrier, has specialized tight junctions that do not allow ions to pass freely and has very low hydraulic conductivity and transcellular transport. This special configuration modifies Starling's forces in the brain microcirculation such that ions retained in the vascular lumen oppose water movement due to hydrostatic pressure. Tight water regulation is necessary in the brain because it has limited capacity for expansion within the skull. Increased intracranial pressure due to vasogenic edema can cause severe neurologic complications and death.

This presentation describes various aspects of the regulation of tissue oxygenation, including the roles of the circulatory system, respiratory system, and blood, the carrier of oxygen within these components of the cardiorespiratory system. The respiratory system takes oxygen from the atmosphere and transports it by diffusion from the air in the alveoli to the blood flowing through the pulmonary capillaries. The cardiovascular system then moves the oxygenated blood from the heart to the microcirculation of the various organs by convection, where oxygen is released from hemoglobin in the red blood cells and moves to the parenchymal cells of each tissue by diffusion. Oxygen that has diffused into cells is then utilized in the mitochondria to produce adenosine triphosphate (ATP), the energy currency of all cells. The mitochondria are able to produce ATP until the oxygen tension or PO2 on the cell surface falls to a critical level of about 4–5 mm Hg. Thus, in order to meet the energetic needs of cells, it is important to maintain a continuous supply of oxygen to the mitochondria at or above the critical PO2 . In order to accomplish this desired outcome, the cardiorespiratory system, including the blood, must be capable of regulation to ensure survival of all tissues under a wide range of circumstances. The purpose of this presentation is to provide basic information about the operation and regulation of the cardiovascular and respiratory systems, as well as the properties of the blood and parenchymal cells, so that a fundamental understanding of the regulation of tissue oxygenation is achieved.

Hypertension is a condition which affects millions of peopleworldwide and its treatment greatly reduces the risk of strokes andheart attacks. This fully revised and updated edition of the ABCof Hypertension is an established guide providing all thenon-specialist needs to know about the measurement of bloodpressure and the investigation and management of hypertensivepatients. This new edition provides comprehensively updated andrevised information on how and whom to treat. The ABC of Hypertension will prove invaluable to generalpractitioners who may be screening large numbers of patients forhypertension, as well as nurse practitioners, midwives and otherhealthcare professionals.

Research centering on blood flow in the heart continues to hold an important position, especially since a better understanding of the subject may help reduce the incidence of coronary arterial disease and heart attacks. This book summarizes recent advances in the field; it is the product of fruitful cooperation among international scientists who met in Japan in May, 1990 to discuss the regulation of coronary blood flow.

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

New updated edition first published with Cambridge University Press. This new edition includes 29 chapters on topics as diverse as pathophysiology of atherosclerosis, vascular haemodynamics, haemostasis, thrombophilia and post-amputation pain syndromes.

The kidney is innervated with efferent sympathetic nerve fibers reaching the renal vasculature, the tubules, the juxtaglomerular granular cells, and the renal pelvic wall. The renal sensory nerves are mainly found in the renal pelvic wall. Increases in efferent renal sympathetic nerve activity reduce renal blood flow and urinary sodium excretion by activation of α1-adrenoceptors and increase renin secretion rate by activation of β1-adrenoceptors. In response to normal physiological stimulation, changes in efferent renal sympathetic nerve activity contribute importantly to homeostatic regulation of sodium and water balance. The renal mechanosensory nerves are activated by stretch of the renal pelvic tissue produced by increases in renal pelvic tissue of a magnitude that may occur during increased urine flow rate. Under normal conditions, the renal mechanosensory nerves activated by stretch of the sensory nerves elicits an inhibitory renorenal reflex response consisting of decreases in efferent renal sympathetic nerve activity leading to natriuresis. Increasing efferent sympathetic nerve activity increases afferent renal nerve activity which, in turn, decreases efferent renal sympathetic nerve activity by activation of the renorenal reflexes. Thus, activation of the afferent renal nerves buffers changes in efferent renal sympathetic nerve activity in the overall goal of maintaining sodium balance. In pathological conditions of sodium retention, impairment of the inhibitory renorenal reflexes contributes to an inappropriately increased efferent renal sympathetic nerve activity in the presence of sodium retention. In states of renal disease or injury, there is a shift from inhibitory to excitatory reflexes originating in the kidney. Studies in essential hypertensive patients have shown that renal denervation results in long-term reduction in arterial pressure, suggesting an important role for the efferent and afferent renal nerves in hypertension.