Overvoltage

Introduction
Measures of Corrosion Rate
Exchange Current Density; Kinetics at Equilibrium
Overvoltage
Activation Overvoltage
Development of Butler–Volmer Equation
Tafel Equation
Low-field Approximation
Multistep Reactions
The Hydrogen Evolution Reaction
Mixed Potential Theory
Effect of Multiple Oxidizing Agents
Galvanic Corrosion
Ohmic Potential Drops
Polarization Resistance and Linear Polarization

1. The effects of acetylcholine (ACh) on excitatory postsynaptic potentials (EPSPs) evoked by stimulating Schaffer-commissural afferents and on ionophoretically applied L-glutamate ligands, were investigated in CA1 neurones of hippocampal slices using current- and voltage-clamp techniques. 2. ACh produced a transient suppression followed by a long-lasting facilitation of EPSPs. The facilitation was also seen in Cs(+)-filled cells under voltage-clamp conditions. Both suppressing and facilitating effects were