Special cutaneous receptor organs of fish: IV. Ampullary organs of the nonelectric catfish, Kryptopterus

Abstract

Ampullary organs of the transparent catfish, Kryptopterus bicirrhus, are present in large numbers on the head and in a regular pattern of lines on the body and fins. The organs lie in the epidermis, and have a pore that opens t o the surface. Flattened cells form a roof and walls. On the floor of the organ there are a "seiisory hillock," coniposed o€ spherical receptor cells and columnar supporting cells, and a "secretory hillock" composed of columnar secretory cells. The receptor cells are nonciliated and have only afferent innervation. The organ cavity is filled with jelly. The organs are coinpared with ampullary organs of the weakly electric fish Eigenmannia, ampullae of Lorenzini of Raja, and small pit organs of Amiurus. Structural characteristics of the ampullary organs of Kryptopterus make them especially suitable for electrophysiological studies.

Glycoproteins bound to ion channels mediate detection of electric fields: A proposed mechanism and supporting evidence

“…Anal and tail fins, which contain numerous electroreceptor organs [Wachtel and Szamier, 1969], were dissected from approximately 70 fish and pooled. The preparation was kept in buffer (in mM, 120 NaCl, 3 KCl, 1 CaCl 2 , 2 MgCl 2 , 10 HEPES, pH 7.4) at 4 8C for 1.5 h, and then incubated with 1 g/L hyaluronidase and 1 g/L collagenase for 20 min at 37 8C.…”

“…The ability to detect weak electric and magnetic fields is exhibited by animals throughout the phylogenetic spectrum [Wachtel and Szamier, 1969;Gavalas-Medici and Day-Magdaleno, 1976;Blakemore, 1982;Wiltschkow and Wiltschkow, 1996;Preece et al, 1998;Pettigrew, 1999], but it has proved difficult to explain on a theoretical or mechanistic basis how such fields can be transduced by animal cells. Strong electric fields can directly alter membrane potentials [Reilly, 1998], but fields below about 0.1 V/m seem capable only of physical effects that are indistinguishable from noise [Astumian et al, 1997].…”

“…It occurred to us that an examination of the anatomic organization of the electroreceptor cells in a field-detecting species might provide insight into a general biological model for transduction of weak fields. We chose the glass catfish (Kryptopterus bicirrhis) for this purpose because it contains electroreceptor organs similar in design to those found in many other species [Wachtel and Szamier, 1969;Szabo, 1974]. In Kryptoperus, a typical electroreceptor organ consists of an invagination in the skin that contains 5-20 electroreceptor cells that are innervated by a single afferent neuron; the lumen of the organ is filled with glycoprotein molecules [Wachtel and Szamier, 1969].…”

“…We chose the glass catfish (Kryptopterus bicirrhis) for this purpose because it contains electroreceptor organs similar in design to those found in many other species [Wachtel and Szamier, 1969;Szabo, 1974]. In Kryptoperus, a typical electroreceptor organ consists of an invagination in the skin that contains 5-20 electroreceptor cells that are innervated by a single afferent neuron; the lumen of the organ is filled with glycoprotein molecules [Wachtel and Szamier, 1969]. The organ detects weak fields that occur in the animal's environment and propagate electrotonically to the apical membranes of electroreceptor cells.…”

Microampullary organs of a freshwater eel‐tailed catfish, plotosus (tandanus) tandanus

“…In catfish, the structure of ampullary organs varies from species with no canals and few receptor cells, e.g., Kryptopterus bicirrhus (Wachtel and Szamier, 1969), to those with long canals and hundreds of receptor cells, e.g., Plotosus anguillaris (Friedrich-Freska, 1930;Obara, 1976). Kalmijn (1974) proposed that this difference in structure resulted from differences in environmental conductivity.…”