Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany
‘Bioelectricity’ has been viewed for a long time as a phenomenon observable only in ‘excitable tissue’ such as nerve or muscle – as demonstrated by Luigi Galvani and Alessandro Volta already in the late 18th century. Arguably the nerve impulse or ‘action potential’ is the most spectacular manifestation of bioelectricity and much effort was directed in the 19th and 20th century towards understanding its physico-chemical basis.
In 1902 Julius Bernstein published his ‘Membrane Theory’, which posits, that electrically excitable cells are surrounded by a membrane and that electrical signals across this membrane are due to its ion-specific permeability. Finally, in the early 1950s the British physiologists Alan L. Hodgkin and Andrew F. Huxley were able to show that the nerve impulse is caused by changes in this permeability, which lead to fluxes of the most abundant cations of our body fluid: Sodium (Na+) and potassium (K+).