Special cutaneous receptor organs of fish: III. The ampullary organs of Eigenmannia

Abstract

Ampullary receptor organs of the South American weakly electric gymnotid fish Eigenmannia virescens consist of a pore at the surface of the skin, a canal through the epidermis, and the expanded basal end of the canal in the corium. The cavity of the organ contains a jelly that is filled with fine fibers. The canal wall consists of three to six layers of flattened cells that appear to be derived from the adjacent skin. Along the lumen of the organ the cells are joined by tight junctions. Usually there are four spherical receptor cells in the base of the organ. They are innervated by single neural terminals. These organs are compared to tuberous receptor organs found in the same species, and the functional significance of the fine structure observed in these cells is discussed.

Invaginating Presynaptic Terminals in Neuromuscular Junctions, Photoreceptor Terminals, and Other Synapses of Animals

“…4c). The small vesicles lining the rod are 20–30 nm; interestingly, there also is a cluster of larger postsynaptic vesicles, 40–60 nm, in this species (Szamier and Wachtel 1969; see also Lissmann and Mullinger 1968), suggesting a possible efferent synaptic function. The end of the presynaptic invagination also has two lobes in the South American blind catfish, Pseudocetopsis sp.…”

“…In the weakly electric, South American gymnotid fish, Eigenmannia virescens, the presynaptic rod is up to 3 micrometers long, and about the last third of it extends into the presynaptic invagination. This last part of the rod has two bulbous expansions, one at the base and one in the enlarged ending of the invaginating presynaptic terminal protrusion (Szamier and Wachtel 1969). However, the presynaptic terminal ending has two lobes and the bulbous expansion of the rod extends a branch into each one (Fig.…”

“…Scale bar is 500 nm. b, c Drawings of electroreceptor synapses from a transparent catfish ( b ; Szamier and Bennett 1973) and a weakly electric gymnotid ( c ; Szamier and Wachtel 1969). Both have irregular presynaptic rods surrounded by vesicles.…”

Sensory Biology of Aquatic Animals

“…Pulse marker (A) has large axon terminal(Szamier and Wachtel 1970) and fires one spike per EOD pulse (C)(Bastian 1976). Pulse marker (A) has large axon terminal(Szamier and Wachtel 1970) and fires one spike per EOD pulse (C)(Bastian 1976).…”

Formation of new sensory cells in deafferented tuberous organs of the gymnotid fish Eigenmannia virescens

“…In contrast to the lateral line mechanoreceptors, which receive both afferent and efferent fibers, electroreceptors are innervated by afferent nerve fibers only (Szabo, 1965;Wachtel and Szamier, 1966;Derbin and Szabo, 1968;Lissmann and Mullinger, 1968;Szamier and Wachtel, 1969;Wachtel and Szamier, 1969;Szamier and Wachtel, 1970). Therefore, the degeneration of the sensory and accessory cells seen after deafferentation in the ampullary organ of Kryptopterus biccirhus (Szamier and Bennett, 1973) and in the Lorenzinian ampullae of Torpedo marmorata (Derbin, 1970) is certainly due to the severance of the afferent innervation.…”