Microampullary organs of a freshwater eel-tailed catfish,plotosus (tandanus) tandanus (original) (raw)
Related papers
Zoomorphology, 2009
Ampullary organs of Euristhmus lepturus occur in high densities along the head and in four parallel pathways along the trunk of the body. Large ampullary pores (125–130 μm) are easily distinguishable from other sensory epithelial pores due to the differences in size and the presence of a collar-like structure. Simple, singular ampullary organs of the head region consist of an ampullary pore connected to a long canal with a diameter of 115–175 μm before terminating as a simple ampulla with an external diameter of 390–480 μm. The ampullary canal is composed of 1–2 layers of flattened squamous epithelial cells, the basement membrane and an interlocking collagen sheath. The innermost cells lining the canal wall are adjoined via tight junctions and numerous desmosomes, as are those of the receptor and supportive cells. Canal wall tissue gives rise to a sensory epithelium containing between 242 and 285 total receptor cells, with an average diameter of 11.7 ± 5.3 μm, intermixed with medially nucleated supportive cells. Each receptor cell (21.38 ± 4.41 μm, height) has an apically positioned nucleus and a luminal surface covered with numerous microvilli. Neural terminals abut the basal region of receptor cells opposite multiple presynaptic bodies and dense mitochondria. Supportive cells extend from the ampullary lumen to the basement membrane, which is adjacent to the complex system of collagen fibres.
Distribution and morphology of the ampullary organs of the salmontail catfish,Arius graeffei
Journal of Morphology, 1999
Whole body staining of Arius graeffei revealed that ampullary pores cover the body with their highest densities occurring on the head and lowest densities on the mid-ventral surface. Each ampullary organ consists of a long canal (0.2-1.75 mm) passing perpendicular to the basement membrane, through the epidermis into underlying dermal connective tissues, curving thereafter to run roughly parallel to the epidermis. Histochemical staining techniques (Alcian blue and LillieЈs allochrome) indicate that the canals contain a neutral to acidic glycoprotein-based mucopolysaccharide gel that varies in composition along the length of the canal. Collagen fibers, arranged in a sheath, surround a layer of squamous epithelium that lines each ampullary canal. At the proximal end of the canal, squamous cells are replaced by cuboidal epithelial cells that protrude into the lumen, thus constricting the lumen to form a small pore into the ampulla. The ampulla is lined with receptor and supportive cells. The numerous (60-120) pear-shaped receptor cells bear microvilli on their luminal surface. Two forms of receptor cells exist in each ampullary organ: basal and equatorial receptor cells. Each receptor cell is connected to an unmyelinated nerve. Each receptor cell is surrounded by supportive cells on all but the apex. Tight junctions and underlying desmosomes occur between adjacent receptor and supportive cells. This form of ampullary organ has not previously been described for teleosts.
Ampullary organ morphology of freshwater salmontail catfish, Arius graeffei
Journal of Morphology, 2000
Two types of ampullary organs are present in the skin of the freshwater salmontail catfish, Arius graeffei, each consisting of a short canal (0.2-0.5 mm) oriented perpendicular to the basement membrane and ending in an ampulla. Histochemical staining techniques (Alcian blue and Lillie's allochrome) indicate that the ampullary canals contain an acidic mucopolysaccharide gel, which is uniform in its staining properties along the canals. Type II ampullary organs consist of a canal, the wall of which is lined with cuboidal epithelial cells. The canal opens into an ampulla with 50 -60 receptor cells. Electron microscopy reveals that the pear-shaped receptor cells bear microvilli on their luminal surface and lie adjacent to an unmyelinated neuron. Type III ampullary organs differ from Type II in that the canal wall consists of cells that possess a protein-rich sac at the luminal apex and have a polymorphic nucleus. The canals of Type III ampullary organs open to an ampulla with 8 -30 receptor cells similar in both staining properties and structure to those of the Type II organ. In both types of ampullary organs, supportive cells surround each receptor cell except at the apex of the receptor cell.
Ultrastructure of the ampullary organs of Plicofollis argyropleuron (Siluriformes: Ariidae)
Journal of Morphology, 2015
The morphology of ampullary organs in Plicofollis argyropleuron, collected from a southeast Queensland estuary, was examined by light and electron microscopy to assess the morphological characteristics of teleost ampullary organs in environments with fluctuating salinities. This catfish possesses both macroampullae and microampullae. Both have the typical teleost arrangement of an ampullary pore linked by a canal to a single ampulla that is lined with receptor and supportive cells. The canal wall of macroampullae consists of a collagen sheath, a basement membrane, and two layers of squamous epithelial cells adjacent to the lumen, joined by desmosomes and tight junctions near the surface of the epithelium. Ampullary pore diameters are similar in range for both the macroampullae and the microampullae, with microampullae always arising from the larger pores within a single region of the head. Canal length of the macroampullae is dramatically longer than those of the microampullae. Macroampullae also contain approximately 10 times as many receptor cells compared with the microampullae. In both organs, these pear-shaped receptor cells alternate with supportive cells along the entire luminal surface of the ampulla. The apical region of receptor cells extends into the lumen and bears numerous microvilli. The basal region of receptor cells adjoins to either individual or multiple unmyelinated neural terminals. The coexistence of two markedly different ampullary organ morphologies within a single species support theories concerning the possible multifunctionality of these sensory organs. J. Morphol., 2015. © 2015 Wiley Periodicals, Inc.
Morphology of the ampullae of Lorenzini in juvenile freshwater C archarhinus leucas
Journal of Morphology, 2014
Ampullae of Lorenzini were examined from juvenile Carcharhinus leucas (831-1,045 mm total length) captured from freshwater regions of the Brisbane River. The ampullary organ structure differs from all other previously described ampullae in the canal wall structure, the general shape of the ampullary canal, and the apically nucleated supportive cells. Ampullary pores of 140-205 mm in diameter are distributed over the surface of the head region with 2,681 and 2,913 pores present in two sharks that were studied in detail. The primary variation of the ampullary organs appears in the canal epithelial cells which occur as either flattened squamous epithelial cells or a second form of pseudostratified contour-ridged epithelial cells; both cell types appear to release material into the ampullary lumen. Secondarily, this ampullary canal varies due to involuted walls that form a clover-like canal wall structure. At the proximal end of the canal, contour-ridged cells abut a narrow region of cuboidal epithelial cells that verge on the constant, six alveolar sacs of the ampulla. The alveolar sacs contain numerous receptor and supportive cells bound by tight junctions and desmosomes. Pear-shaped receptor cells that possess a single apical kinocilium are connected basally by unmyelinated neural boutons. Opposed to previously described ampullae of Lorenzini, the supportive cells have an apical nucleus, possess a low number of microvilli, and form a unique, jagged alveolar wall. A centrally positioned centrum cap of cuboidal epithelial cells overlies a primary afferent lateral line nerve. J. Morphol. 000:000-000,
Journal of Structural Biology, 1998
In rocklings, the epidermis of the anterior dorsal fin (ADF) contains approximately 5 million SCCs. High-voltage electron microscopy and three-dimensional reconstructions from serial sections were used to examine the ultrastructure, arrangement, and synaptic contacts of the SCCs in the rockling ADF. Approximately 15% of all cells in the fin ray epidermis are SCCs, which occupy roughly 30% of the epidermal volume. These spindle-shaped cells are 25-30 m long and up to 10 m wide and terminate apically in a microvillus protruding 2-5 m above the epidermal surface. SCCs contain abundant endoplasmic reticulum and a large Golgi apparatus in their proximal regions. The distal parts of SCCs contain characteristic vesicles, elongate mitochondria, and longitudinal strands of intermediate filaments. Synapses between SCCs and nerves resemble those found in teleost taste buds. One to four synaptic contacts per SCC were found. We hypothesize that the apparent secretory activity of the SCCs serves to replenish the apical membrane and mucus. Furthermore, parallel sampling of several hundred SCCs by single nerve fibers may serve low-threshold detection rather than stimulus localization. 1998 Academic Press
Ultrastructure of the lateral-line sense organs of the ratfish, Chimaera monstrosa
Cell and Tissue Research, 1981
The ultrastructure of the lateral-line neuromasts in the ratfish, Chimaera monstrosa is described. The neuromasts rest at the bottom of open grooves and consist of sensory, supporting, basal and mantle cells. Each sensory cell is equipped with sensory hairs consisting of a single kinocilium and several stereocilia. There are several types of sensory hair arrangement, and cells with a particular arrangement form patches within the neuromast. There are two types of afferent synapse. The most common afferent synapse has a presynaptic body and is typically associated with an extensive system ofanastomosing tubules on the presynaptic side. When the tubules are absent, vesicles surround the presynaptic body. These synapses are often associated into synaptic fields, containing up to 35 synaptic sites. The second type of afferent synapse does not have a presynaptic body and is not associated with the tubular system. The afferent synapses of the second type do not form synaptic fields and are uncommon. The efferent synapses are either associated with a postsynaptic sac or more commonly with a strongly osmiophilic postsynaptic membrane. The accessory cells are similar to those in the acoustico-lateralis organs of other aquatic vertebrates. A possibility of movement of the presynaptic bodies and of involvement of the tubular system in the turnover of the transmitter is discussed. A comparison of the hair tuft types in the neuromasts of Ch. monstrosa with those in the labyrinth of the goldfish and of the frog is attempted.
Experimental Brain Research, 2004
The present study was conducted to visualize the ultrastructural features of vestibular efferent boutons in the oyster toadfish, Opsanus tau. The crista ampullaris of the horizontal semicircular canal was processed for and examined by routine transmission electron microscopy. The results demonstrate that such boutons vary in size and shape, and contain a heterogeneous population of lucent vesicles with scattered dense core vesicles. Efferent contacts with hair cells are characterized by local vesicle accumulations in the presynaptic terminal and a subsynaptic cistern in the postsynaptic region of the hair cell. Serial efferent to hair cell to afferent synaptic arrangements are common, particularly in the central portion of the crista. However, direct contacts between efferent terminals and afferent neurites were not observed in our specimens. The existence of serial synaptic contacts, often with a row of vesicles in the efferent boutons lining the efferent-afferent membrane apposition, suggests that the efferent influence on the crista may involve both synaptic and nonsynaptic, secretory mechanisms. Further, it is suggested that differences in more subtle aspects of synaptic architecture and/or transmitter and receptor localization and interaction may render the efferent innervation of the peripheral crista less effective in influencing sensory processing.