Physics of Nerve Cells and Excitatory Membranes

Unique reference explaining how novel concepts in thermodynamics can explain the full range of nerve cell properties and functions

Physics of Nerves and Excitatory Membranes lays out a novel concept for the function of excitatory membranes, nerve cells, and the brain that is based on thermodynamics, demonstrating that the propagation of a nerve pulse, its temporal length, the occurrence of ion channel-like events in nerve membranes, and the action of anesthetics are all rooted in thermodynamic couplings and may be described using the fluctuation-dissipation theorem that is fundamental for thermodynamics. This new view of excitatory membranes differs significantly from the traditional electrophysiological description of nerves that largely neglects the mechanical, thermal, and chemical properties of nerve cells and their membranes and thus struggles to explain important neuronal properties such as the action of general anesthetics.

Physics of Nerves and Excitatory Membranes is didactically written and includes information on:

• The structure and electrical properties of nerves, dimensions and mechanical properties of the nerve pulse, and optical changes during the action potential
• Cable theory, voltage gating, the Hodgkin-Huxley model, and protein ion channels
• Membrane structure and melting, phase behavior, domains, and rafts, and the influence of voltage, drugs, proteins, pH, and ionic strength
• Heat capacity, sound propagation, relaxation timescales, and capacitance and capacitive susceptibility
• Voltage-gated and mechanosensitive lipid channels, temperature sensing, and selectivity of lipid channels

Physics of Nerves and Excitatory Membranes is of prime interest for biophysicists studying biomembranes as well as for neurobiologists and clinical researchers studying anesthesia. Its accessible style makes it very well suited for teaching the subjects that it covers. Part I: INTRODUCTION
I.1 Early Nerve Studies
I.2 The early period of electrophysiology
I.3 The Hodgkin-Huxley model and beyond
I.4 Another line of thought
I.5 Scope of this book
Part II: THERMODYNAMICS
II.1 Fundamental laws in thermodynamics
II.2 Some statistical Thermodynamics
II.3 Entropy
II.4 The fluctuation relations
Part III: PROPERTIES OF NERVES
III.1 Structure of nerves
III.2 Electrical properties of nerves
III.3 The dimensions of the nerve pulse
III.4 Mechanical properties of the nerve pulse
III.5 Optical changes during the action potential
III.6 Heat production and temperature changes during the nerve pulse
III.7 Magnetic fields generated during the action potential
III.8 Collisions of nerve pulses
Part IV: BASIC PRINCIPLES OF ELECTROPHYSIOLOGY
IV.1 Some historical considerations
IV.2 Cable theory
IV.3 Voltage Gating
IV.4 The Hodgkin-Huxley model
IV.5 Implications of the Hodgkin-Huxley model
Part V: PROPERTIES OF ARTIFICIAL AND BIOLOGICAL MEMBRANES
V.1 Membrane Structure
V.2 Membrane Melting
V.3 Phase behavior, domains and rafts
V.4 Influence of hydrostatic pressure and lateral pressure
V.5 Curvature
V.6 Influence of pH and ionic strength
V.7 Influence of Voltage
V.8 Influence of Drugs and proteins
Part VI: FLUCTUATIONS AND SUSCEPTIBILITIES
VI.1 Entropy and fluctuations
VI.2 Heat capacity
VI.3 Relation between enthalpy, volume and area changes
VI.4 Transitions and elastic constants
VI.5 Sound propagation
VI.6 Capacitance and capacitive susceptibility
VI.7 Relaxation timescales
Part VII: THE SOLITON THEORY
VII.1 Hydrodynamics and sound propagation
VII.2 Sound velocity in nerve membranes
VII.3 The frequency dependence of the sound velocity
VII.4 The nerve pulse as an electromechanical soliton
VII.5 Nerve contraction and pulse trains
VII.6 Excitation of solitons
VII.7 Pulse collisions
VII.8 Pulses on monolayers
Part VIII: CHANNELS
VIII.1 Protein ion channels
VIII.2 The permeability of lipid membranes
VIII.3 Voltage-gated lipid channels
VIII.4 Mechanosensitive lipid channels
VIII.5 Temperature sensing
VIII.6 The influence of drugs on membrane permeability and lipid ion channels
VIII.7 Channel lifetimes
VIII.8 Selectivity of lipid channels
VIII.9 Proteins as catalysts for lipid channel formation
Part IX: MEDICAL CONSEQUENCES
IX.1 Factors that influence excitation thresholds
IX.2 Anesthesia
IX.3 Adaptation
IX.4 Nerve Stretching
IX.5 Tremor and lithium
IX.6 Ultrasound neurostimulation

Thomas Heimburg is Professor for Biophysics at the Niels Bohr Institute of the University of Copenhagen (Denmark), where he is the head of the Membrane Biophysics Group. His research focuses on theoretical and experimental thermodynamics of biological systems, including biomembranes, artificial lipid membranes, and proteins. He is the author of the book Thermal Biophysics of Membranes (Wiley-VCH, 2007) and an Editorial Board member of the journal Biophysical Chemistry.