Electrical synapses are uncommon in normal mammalian neurones, where chemical transmission is the main form of communication between cells. Electrical synapses however do occur between astrocytes and allow them to coordinate their activities.
Electrical synapses occur where the cell membranes of two cells come into very close contact, and are joined together by proteins called connexins, which form gap junctions. Ions can pass through gap junctions in either direction and electrical events in one cell are quickly mimicked by the adjacent cell.
The intercalated disc between cardiac myocytes is a site where gap junctions are found, and the transmission of the cardiac action potential between adjacent myocytes occurs because of these junctions.
Key Words : electrical synapses, connexins
Gap Junctions involve the fusion of the membranes of two cells using proteins called connexins. The gap junctions vary in size and allow ions to move quickly between cells in either direction, so that the electrical activity of one astrocyte can influence the adjacent astrocytes.
Electrical Synapses are close junctions between cells that allow instantaneous electrical communication between them. This form of communication is not commonly used by mammaian nerve cells.
Connexins are proteins that connect adjacent cells and allow current to flow between them. One example is the intercalated disc between adjacent cardiac myocytes, which allows current to spread across the myocardium making it a functional syncitium.
In the CNS gap junctions often occur between astrocytes. This helps to control the environment around synapses, as the astrocytes are involved in the metabolism and recycling of transmitters such as glutamate and GABA.