Scanning electron microscopy of the electric tissue of Narcine brasiliensis.

The anatomy of electroplaques of Narcine brasiliensis has been studied by scanning electron microscopy. The ventral faces of the plaques are innervated with an abundance of branching nerves in close contact with the underlying (postsynaptic) membrane. Large numbers of troughs and evaginations of the postsynaptic membrane serve to increase its surface area. Fibroblasts are closely associated with the dorsal faces which appear covered with a matrix of fibrous material. Well-washed dorsal surfaces of single electroplaques are free of this matrix. The dorsal surface area is considerably increased by tubules extending into, and projections out of, the surface.