Ion-Selective Microelectrodes and Their Use in Excitable Tissues

The Symposium on "Ion Selective Microelectrodes and Their Use in Excitable Tissues" was held in Prague from July 8-11, 1980. It was organized by the Institute of Physiology of the Czechoslovak Academy of Sciences as a satellite symposium of the XXVIII Interna­ tional Congress of Physiological Sciences in Budapest. Sixty parti­ cipants met for three days in the historical setting of the Strahov Monastery. The informal and relaxed atmosphere of the scientific sessions, together with the social programme made the meeting a success and helped to cement old friendships and to form new ones. The organizers were happy to welcome as participants representatives from most of the laboratories working with ion-selective microelectrodes (ISMs) in the world. Neurophysiological research with liquid ion-exchanger ISMs in the Prague laboratory was started as early as 1971 due to the fact that one of us (P. H. ) had the opportunity of learning the technique directly from Dr. J. L. Walker in Salt Lake City. It was thanks to his patience and, later, his courtesy in providing us with the liquid ion-exchanger for potassium and silicone that we were able to get a start in what turned out to be, in a year or so, very strong international competition. This volume contains the papers presented at the Symposium. It is divided according to the actual sessions with names of the chair­ men, who helped the organizers to make the Symposium a real success.

Session I. Electrochemistry of the ISM and Ionophores for the ISM.- Theory of Ion-Selective Electrodes.- New Ion Selective Liquid Membrane Microelectrodes.- Sensitivity of K+-Selective Microelectrodes to pH and Some Biologically Active Substances.- Double-Barrel Ion Selective [K+, Ca2+, Cl?] Coaxial Microelectrodes ISCM for Measurements of Small and Rapid Changes in Ion Activities.- Determination of Selectivity Coefficients of Ion-Selective Microelectrodes.- Session II. Intracellular Measurements of Ionic Activity.- Intracellular Potassium and Chloride Measurements in Sheep Cardiac Purkinje Fibers.- Intracellular Electrochemical Potentials: Skeletal Muscle vs. Epithelial Steady-State vs. Kinetics.- Measurement of Intracellular Calcium Activities.- pH Related Potassium Movements in Rabbit Atrium.- Intracellular Free Calcium Affects Electric Membrane Properties. A Study with Calcium-Selective Microelectrodes and with Arsenazo III in Helix Neurons.- Measurements of Free Ca2+ in Nerve Cell Bodies.- Intracellular Recording of Potassium in Neurons of the Motor Cortex of Awake Cats Following Extracellular Applications of Acetylcholine.- Potassium Fluxes of Isolated Nerve Endings Monitored by a Valinomycin-Activated Ion-Selective Membrane electrode in vitr..- Session III. Ion Activities in the Spinal Cord and Their Physiological Significance.- Extracellular K+ Accumulation in the Spinal Cord.- Extracellular Potassium and Calcium Activities in the Mammalian Spinal Cord, and the Effect of Changing Ion Levels on Mammalian Neural Tissues.- Relations Between Extracellular K+ and Ca++ activities and Local Field Potentials in the Spinal Cord of the Rat during Focal and Generalized Seizure Discharges.- Ion Fluxes Across the Membrane of Motoneurons during the Action of Glutamate.- The Ionic Basis of the IPSP in Spinal Motoneurones of the Frog.- Effects of Increased Extracellular Potassium Activity in the Frog Spinal Cord on the Flexor Reflex.- Extracellular K+ Activity During Electrical Stimulation of Rat Sympathetic Ganglia, Vagus and Optic Nerves in vitr..- Extracellular Potassium Activity and Axon Excitability.- Session IV. Ionic Activity Changes in the Brain and their Physiological Significance.- Extracellular Potassium, Calcium and Volume Profiles During Spreading Depression.- Cortical pH and pCa in Relation to DC Potential Shifts During Spreading Depression and Asphyxiation.- Changes of Extracellular Potassium in Rat Cerebellar Cortex Indicate a Reduced Na-K-Pump Activity During Acute and Chronic Li-Application.- Changes in Extracellular Free Ca2+ in the Sensorimotor Cortex of Cats During Electrical Stimulation and Iontophoretic Application of Amino-Acids.- Measurements of Ion Activity in the CNS: Extracellular K+ and Ca in the Hippocampus.- Evoked Ionic Alterations in Brain Slices.- Serotonin and GABA-Induced Fluctuations in Extracellular Ion Concentration in the Hippocampal Slice.- The Slow Component of the Direct Cortical Response and Extracellular Potassium.- Potassium Changes Elicited in the Feline Somatosensory Cortex by a Single Stimulus to the Peripheral Nerve.- The Mechanism and Integrative Role of Extracellular Potassium Clearance in the Rat Brain.- Session V. Ionic Activity Changes in the Heart and Skeletal Muscle.- K+ Accumulation and its Physiological Regulatory Effects in Heart Muscle.- Measurement of Intracellular Ionic Calcium Concentration in Guinea Pig Papillary Muscle.- Intracellular Na Activity During K or Rb Activated Response in Sheep Purkinje Fibres. Correlation with Changes in Membrane Potential.- Interaction between pHi, and pCai, in Cardiac Tissue.- The Use of ISMs in Working Skeletal Muscle and Venous Effluent Blood.- Characteristics of Ca2+-Selective Microelectrodes and Their Application to Cardiac Muscle Cells.- Session VI. Other Techniques for the Study of Ionic Activity Changes in Brain Research.- Ion-Selective Properties of the Nerve Cell Membrane.- Glial Cells as Potassium Detectors.- The Role of Cells in the Dispersal of Brain Extracellular Potassium.- Movement of Potassium into Glial Cells in the Retina of the Drone, Apis Mellifera, During Photostimulation.- Intracellular Calcium and the Regulation of Neuronal Membrane Permeability.- CNS and Na-Pump in in sit. Muscle.- Participants.