The importance of bioelectrical potentials at fertilization

Fertilization is the first step of a new life, and it occurs only if the sperm could succeed to fuse with the egg membrane. The egg should have a stable resting membrane potential so that a sperm can penetrate it. Just after the sperm fertilizes the egg, its resting membrane potential shifts suddenly, which is generally a depolarization in most species. This potential shift (Fertilization potential) establishes a block for the second sperm entry. However, some activators other than the sperm can also trigger this potential change (Activation potential). From the beginning of this century, researchers dealing with fertilization studies tried to clarify the role of these bioelectrical potentials at fertilization on various types of species, by using electrophysiological techniques. In this paper, the importance and functions of bioelectrical potentials at fertilization are reviewed