On 15 November 1997, the first international symposium "Neural and Chemical Control of Breathing: Pharmacological and Clinical Aspects" was held at Leiden University Medical Center on the occasion of the retirement of one of the members of the Control of Breathing Research Group of the Departments of Physiology and Anesthesiology, Dr. Aad Berkenbosch. Among others, Dr. Berkenbosch, played an important role in this research group, which made a large and significant contribution to scientific research on the regulation of breathing. This book presents the proceedings of that meeting together with papers of several authors who have strong bonds with the Leiden Departments of Physiology and Anesthesiology. All studies represent state of the art work on the subject of respiratory control and cardiovascular medicine, with emphasis on the physiological, pharmacological and anesthesiological aspects of both fields. The book is divided in several sections: Oxygen Physiology. Prof. John Severinghaus presents among other things his ideas on oxygen sensing and high altitude related diseases. Prof. Honda gives results from studies in a unique set of subjects without carotid bodies. The findings of Honda's group support the idea that an intact hypoxic drive from the carotid bodies is necessary for the generation of central hypoxic depression. Dr. Hans van Beek discusses the effects of hypoxia and hypercapnia on cardiac contractility in animal models. Prof. Oeseburg demonstrates the feasibility of Near Infra Red Oximetry for monitoring tissue oxygenation in patients. Central Chemoreception.

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.

Respiration is one of the most basic motor activities crucial for survival of the individual. It is under total control of the central nervous system, which adjusts respiratory depth and frequency depending on the circumstances the individual finds itself. For this reason this volume not only reviews the basic control systems of respiration, located in the caudal brainstem, but also the higher brain regions, that change depth and frequency of respiration. Scientific knowledge of these systems is crucial for understanding the problems in the many patients suffering from respiratory failure. This well-established international series examines major areas of basic and clinical research within neuroscience, as well as emerging subfields

Hopefully, this book will be taken off of the shelf frequently to be studied carefully over many years. More than 40 researchers were involved in this project, which examines respiration, circulation, and metabolism from ?sh to the land vertebrates, including human beings. A breathable and stable atmosphere ?rst appeared about 500 million years ago. Oxygen levels are not stable in aquatic environments and exclusively water-breathing ?sh must still cope with the ever-changing levels of O 2 and with large temperature changes. This is re?ected in their sophisticated count- current systems, with high O extraction and internal and external O receptors. 2 2 The conquest for the terrestrial environment took place in the late Devonian period (355–359 million years ago), and recent discoveries portray the gradual transitional evolution of land vertebrates. The oxygen-rich and relatively stable atmospheric conditionsimpliedthatoxygen-sensingmechanismswererelativelysimpleandl- gain compared with acid–base regulation. Recently, physiology has expanded into related ?elds such as biochemistry, molecular biology, morphology and anatomy. In the light of the work in these ?elds, the introduction of DNA-based cladograms, which can be used to evaluate the likelihood of land vertebrates and lung?sh as a sister group, could explain why their cardio-respiratory control systems are similar. The diffusing capacity of a duck lung is 40 times higher than that of a toad or lung?sh. Certainly, some animals have evolved to rich high-performance levels.