Electric organ

The electric organ is a myogenic organ common to all electric fish used for the purposes of creating an electric field, a behavior used for navigation as well as communication in natural environments.

Electrocytes
Electrocytes, electroplaques or electroplaxes are cells used by rays, electric eels and other electric fish for electrogenesis and electroreception. They are flat disk-like cells that are stacked in a sequence in a manner similar to a battery. Electric eels have several thousand of these cells stacked, each producing 0.15V. The cells function by pumping positive sodium and potassium ions out of the cell via transport proteins powered by adenosine triphosphate. Postsynaptically, electrocytes work much like muscle cells. They have nicotinic acetylcholine receptors. These cells are used in research because of their resemblance to nerve-muscle junctions.

Firing
To discharge the electrocytes at the correct time, the electric eel uses its pacemaker nucleus, a nucleus of pacemaker neurons. When an electric eel spots its prey, the pacemaker neurons fire and acetylcholine is subsequently released from electromotor neurons to the electrocytes, resulting in an electric organ discharge.

Location
In the electric Torpedo Ray, electroplaxes are found near the pectoral muscles and the gills. In all other fishes, it is often near the tail. In one fish genus, the electric catfish Malapterurus, the electric organs are not made of individual electroplax, but are built up from charges of the epithelium, specifically the skin.

Electric Organ Discharge
Electric organ discharge (EOD) is the electric discharge generated by the organs of animals including electric fish. In some cases the electric discharge is strong and is used for protection from predators; in other cases it is weak and it is used for navigation and communication.