Ion Flux in Pulmonary Vascular Control, 1993 NATO Science Series A: Series, Vol. 251

6 Ions can pass through a single membrane channel at a rate of 10 ions/second. Over the last decade the ability to measure ion flux so precisely and to document the opening and closing of individual ion channels has provided a powerful tool to those working on smooth muscle physiology and vascular reactivity. The use of potassium channel blockers by Tom Lloyd in the 1960s and calcium channel blockers by Ivan McMurtry in the 1970s indicated the importance of ion flux in regulating pulmonary vascular tone. Recent advances in technology. principally the patch-clamp technique and fluorescent ion-sensitive dyes. now permit a more detailed description of physiologic mechanisms. This volume arises from the Sixth Grover Conference on the Pulmonary Circulation. a NATO Advanced Research Workshop. held in Colorado in October 1992. A group of international sCientists who are leaders in the field of ion flux focused their attention on the problems of the pulmonary vasculature. The chapters in this book describe the present state of knowledge of the movement and storage of ions in vascular endothelial and smooth muscle cells. Those who are not familiar with the techniques of patch clamping and calcium imaging will find an introduction to these methods in the chapters by Leblanc and Wan and Archer et al. The role of potassium channels in oxygen sensing illustrates the rapid progress which the study of ion currents has made possible.

Pulmonary Hypertension: From Phenomenology to a Molecular Understanding of Disease Mechanisms.- The Electrophysiology of Smooth Muscle Cells and Techniques for Studying Ion Channels.- Calcium Control in Smooth Muscle.- Calcium Channels in Arterial Smooth Muscle Cells.- Interactions of Intracellular Ca2+ Pools in Vascular Smooth Muscle.- Na-Ca Exchange in Isolated Coronary Myocytes: A Study Combining Voltage clamp and Ca2+ Fluorometry2+ Pools in Vascular Smooth Muscle.- Role of Calcium ATPases in Pulmonary Vascular Reactivity.- Fast Na+ Current and Ca2+ Currents in Smooth Muscles.- Influence of Physical and Environmental Factors on Ion Channels in Arterial Muscle.- Potassium Channels in Vascular Smooth Muscle.- Potassium Channels Activated by Calcium Released from the Sarcoplasmic Reticulum in Vascular Smooth Muscles.- ATP-Sensitive Potassium Channels in the Pulmonary Vasculature.- Electrophysiological Actions of Extracellular ATP Application.- An ATP-Activated Potassium Channel in Smooth Muscle Cells from the Pulmonary Artery.- The Effect of Prostacyclin Analogs on Vascular K Channels.- Potassium Channels and Oxygen Sensing.- Potassium Channel Modulated by Hypoxia and the Redox Status in Glomus Cells of the Carotid Body.- Redox Regulation of Potassium Channels and Hypoxic Pulmonary Vasoconstriction.- The Sodium Gradient, Potassium Channels, and Regulation of Calcium in Pulmonary and Mesenteric Arterial Smooth Muscle: Effects of Hypoxia.- Ion Flux in Vascular Endothelial Cells.- The Importance of Calcium in the Regulation of EDRF Synthesis in the Pulmonary Vasculature.- The Role of Ion Channels in Vascular Endothelium.- Calcium Signalling in Vascular Endothelial Cells: Calcium Entry and Release.- Mechanosensitive Ion Channels in Vascular Endothelial Cells.- Membrane Hyperpolarization as a Mechanism for Endothelium-Dependent Vasodilation.- The Interaction between Flow-Induced Vasoconstriction and Vasodilation: A Mechanism for Setting the Level of Vascular Tone.- Therapy of Pulmonary Hypertension.- Correlation of Acute Prostacyclin Response in Primary (Unexplained) Pulmonary Hypertension with Efficacy of Treatment with Calcium Channel Blockers and Survival.- Role of Endothelium-Derived Nitric Oxide in Perinatal Pulmonary Vasoregulation.