[Multiplicity of calcium permeabilities]

In this review, we deal with recent progress on calcium currents in neuronal membrane. Most of the results discussed have come from the use of the patch clamp technique which allows one to record currents of small amplitude (a few tens of pA in the whole-cell configuration or less than the pA with excised patches), and to impose a calcium gradient across the membrane. This allows access to the elementary currents and a pharmacology of the Ca channels is developed.