Ion Channels

1 Fluorescence Spectroscopy to Probe the Structure and Cellular Dynamics of Ion Channels.- 1. Introduction.- 2. Methods, Principles, and Utility of Fluorescence Spectroscopy.- 2.1 Principles of Fluorescence.- 3. Selection, Design, and Utilization of Ion Channel Probes.- 3.1. Chemical Requirements.- 3.2. Spectroscopic Requirements.- 3.3. Preparation and Characterization of Fluorescent Ion Channel Probes.- 4. Fluorescence Spectroscopy of the Voltage-Dependent Na + Channel.- 4.1. Molecular Environment and Conformational Fluctuations of the Voltage-Dependent Na+ Channel Receptor Sites.- 4.2. Structural Mapping of the Na+ Channel by Fluorescence Resonance Energy Transfer: Molecular Organization of the Channel Receptor Sites.- 5. Cellular Mapping of Na+ Channels in Excitable Tissues.- 5.1. Use of Fluorescent Neurotoxin Probes.- 5.2. Localization of Na+ Channels by Fluorescence Microscopy.- 5.3. Regionalization and Lateral Mobility of Voltage-Dependent Na+ Channels.- 5.4. Localization and Mobility of Other Ion Channels in Nerve and Muscle.- 6. Conclusion.- 7. References.- 2 M Currents.- 1. Prologue.- 2. M Current.- 3. M-Current Kinetics.- 4. Physiological Function.- 4.1. Contribution of IM to the Resting Membrane Potential.- 4.2. Control of Membrane Potential Change.- 4.3. Control of Excitability.- 5. Pharmacology of M Current.- 5.1. Cholinergic Agonists.- 5.2. Receptors.- 5.3. Peptides.- 5.4. Nucleotides.- 5.5. K-Channel Blockers.- 5.6. Organic K-Channel Blockers.- 5.7. Transduction Mechanisms for IM Inhibition.- 6. Synaptic Inhibition of M Current.- 6.1. Frog Sympathetic Neurons.- 6.2. Slow epsp.- 6.3. Late Slow epsp.- 6.4. Mammalian Sympathetic Neurons.- 6.5. Hippocampal Neurons.- 6.6. Functional Effects of IM-Driven Synaptic Potentials.- 7. Future Work.- 8. References.- 3 Macromolecular Sites for Specific Neurotoxins and Drugs on Chemosensitive Synapses and Electrical Excitation in Biological Membranes.- 1. Introduction.- 2. Voltage and Patch Clamping.- 3. Impact of Neurotoxins in Molecular Pharmacology.- 3.1. The Sodium Channel.- 3.2. The Potassium Channel.- 3.3. The Nicotinic Acetylcholine Receptor/Channel Complex.- 4. The Histrionicotoxins.- 4.1. History.- 4.2. Effect of the Histrionicotoxins on Sodium and Potassium Channels.- 4.3. Effect of the Histrionicotoxins on the Nicotinic AChR.- 4.4. Comparative Effects of the Histrionicotoxins in Dendrobatid and Rana Frogs.- 5. Summary.- 6. References.- 4 Developmental Changes in Acetylcholine Receptor Channel Properties of Vertebrate Skeletal Muscle.- 1. Introduction.- 2. Materials and Methods.- 2.1. Experimental Animals.- 2.2. Electrophysiological Techniques.- 3. Results.- 3.1. Two Types of ACh Receptor Channels in the Adult Animal.- 3.2. Two Types of ACh Receptor Channels in the Young Animal.- 3.3. Two Types of ACh Receptor Channels in Cultured Muscle Cells.- 3.4. Developmental Changes of ACh Receptor Channel Kinetics.- 3.5. Correlation between Channel Conversion and Other Developmental Changes.- 4. Discussion.- 5. Postscript.- 6. References.- 5 Intracellular ATP and Cardiac Membrane Currents.- 1. Introduction.- 2. Techniques for the Single Cardiac Cell.- 2.1. Single Cardiac Cell Preparation.- 2.2. Single Channel Recordings.- 2.3. Intracellular Microinjection and Whole-Cell Current Recording.- 2.4. Whole-Cell Voltage Clamp and Internal Dialysis.- 3. Whole-Cell Current and Intracellular ATP Level.- 3.1. ATP Level and the Membrane Current.- 3.2. Effects of Other Nucleotides and Related Substances.- 4. ATP-Sensitive K Channel.- 4.1. Conductance Properties.- 4.2. Kinetic Properties.- 4.3. Nature of the ATP-Binding Site.- 4.4. Contribution to the Whole-Cell Current.- 5. Effects of ATP on Other K Channels.- 6. Conclusion.- 7. References.- 6 Calcium Antagonist Receptors.- 1. Introduction.- 2. Radioreceptor Binding Studies.- 2.1. Dihydropyridine Ligands.- 2.2. Phenylalkylamine Ligands.- 2.3. Other Ligands.- 3. Atypical Actions of Calcium Antagonists.- 3.1. Nonspecific Actions of Calcium Antagonists.- 3.2. Atypical Calcium Antagonists.- 4. The Relation of Calcium Antagonist Receptors to Voltage-Sensitive Calcium Channels.- 4.1. Experimental Design.- 4.2. Experimental Findings.- 5. Future Developments in Calcium Antagonist Receptors.- 6. References.- 7 The Amiloride-Blockable Sodium Channel of Epithelial Tissue.- 1. Introduction.- 2. Na+ Uptake at the Apical Membrane.- 2.1. Na+ Channel "Self-Inhibition".- 2.2. Amiloride Block of the Apical Na+ Conductance.- 2.3. Regulation of Apical Na+ Channel.- 3. A6 Cells as a Model for Kidney Distal Tubule.- 3.1. Problems with Native Tissues.- 3.2. A6 Cell Origin and Properties.- 3.3. Additional Advantages of A6 Cells.- 4. Single Na + Channel Activity.- 4.1. Different Subtypes of Na+ Channels.- 4.2. Differences between Single Channel and Macroscopic Measurements.- 4.3. Patch-Clamp Studies of Na +-Transporting Cells.- 4.4. Does Na + Channel Conductance Saturate?.- 5. A Model for the Regulation of Apical Na+ Permeability.- 6. Future Work.- 7. References.- 8 Ionic Channels in Ocular Epithelia.- 1. Introduction.- 2. Low-Noise Methods and Glass Considerations.- 2.1. Noise Performance.- 2.2. Comments on Glass.- 3. General Approach to Channel Identification.- 4. Selectivity.- 4.1. Experimental Characterization of Channel Types.- 4.2. Identification of Channels: Practical Problems.- 4.3. Need for Accurate Reversal Potential Measurements.- 4.4. Errors from Artifactual Offset Potentials.- 5. Current-Voltage Relations.- 6. Kinetics of Gating.- 6.1. Difficulties in Estimating Kinetics.- 6.2. Channel Density.- 6.3. Kinetics in Patches with Several Channels.- 6.4. Patches with Different Channel Types.- 7. Characterization of Blockers.- 8. Channel Types Observed in Ocular Epithelia.- 8.1. Nonselective Cation Channels.- 8.2. Anion Channels.- 8.3. Sodium Channels.- 8.4. Calcium Channels.- 8.5. Potassium Channels.- 8.6. Channel Types in Different Cells and Species.- 8.7. Summary of Diversity.- 9. References.