Electroplaques

From Freepedia

Electrocytes, electroplaques or electroplaxs 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 fires and acetylcholine is subsequently released from electromotor neurons to the electrocytes, resulting in an electric organ discharge.

Location

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