[The development of the concept of neuronal resting potential. Fundamental and clinical aspects]

Since the classical works carried out on the squid giant axon far less attention has been directed towards the study of the resting membrane potential than to the study of changes in potential (action potential, synaptic potentials, and so forth). It is often assumed that the resting potential depends on an independent current of the voltage called the leakage current, although, except on rare occasions, it has not been possible to characterise such a current either pharmacologically or molecularly. In this work our aim is to review and update the concept of resting potential.

The outlook at present offers a complex situation in which several factors, in addition to leakage currents, play a role in maintaining resting potentials. These factors include ionic currents across non-inactivating voltage-dependent channels, the sodium/potassium pump, and certain currents with characteristics that are similar to those of the classical leakage current. The interaction of all these components gives rise to complex sub-threshold behaviours in the neurons, such as intrinsic rhythmic oscillations, which leads us away from the passive concept of the resting potential.

An ever-increasing number of descriptions of intrinsic sub-threshold, rhythmic activity are being reported, which could suggest that they are a generalised phenomenon in the nervous system. Further studies need to be conducted into the complex mechanisms that determine the resting potential in order to gain an understanding of the phenomena of neuronal excitability and to find an explanation for some of the many pathological conditions that affect the nervous system.