electrocyte

An electrocyte is a specialized, non-contractile cell that forms the functional unit of the electric organ in certain fish. Electrocytes generate electric discharges used for navigation and sensing (electrolocation), communication, and predation. They act as biological voltage sources, producing currents when activated.

Structurally, electrocytes are large, flattened or elongated cells with membranes oriented on opposite faces. They are typically arranged in series within the electric organ, so the voltages produced by individual cells add together to create a strong overall discharge. The surface membranes house a high density of voltage-gated ion channels, enabling rapid ion flux and transient depolarizations that contribute to the electric output.

Functionally, electrocytes can arise from different developmental lineages. In myogenic electric organs, electrocytes originate from skeletal muscle cells and lose contractile function, yet retain excitability. In neurogenic electric organs, neural circuits directly drive the discharge. Regardless of origin, synchronized activation of many electrocytes yields powerful, organism-wide electrical discharges.

Distribution and evolutionary context vary among electric fishes. Myogenic electric organs are found in several groups of South and Central American and African freshwater fishes, such as some gymnotiforms and mormyrids, whereas neurogenic electric organs occur in other lineages like certain rays. The diversity of electrocyte organization reflects adaptations to prey capture, mate signaling, and environmental navigation.

Research on electrocytes informs broader topics in bioelectricity, cell differentiation, and the evolution of electric communication and sensing systems in animals.