On the Development of Electroreceptive Ampullary Organs of Triturus alpestris (Amphibia: Urodela)

1986 ◽  
Vol 7 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Dorothea Bolz ◽  
Bernd Fritzsch
Keyword(s):  
Striking Similarity ◽  
Sensory Cells ◽  
Lateral Line System ◽  
Functional Constraints ◽  
Supporting Cells ◽  
Line System ◽  
Triturus Alpestris ◽  
Alpine Newt ◽  
Ampullary Organ ◽  
Number Of Cells

AbstractThe ontogenesis of the organs of the lateral-line system of the alpine newt (Triturus alpestris) was examined with special emphasis on the ampullary organs using resin embedded thick sections. The mechanoreceptive neuromasts and the electroreceptive ampullary organ were indistinguishable prior to hatching. At hatching only few ampullary organs were found around the eye. These organs consist of one or two egg-shaped sensory cells and a few supporting cells. The ratio of ampullary organs and neuromasts changes from 1:15.6 (stage 36) to 1:1.1 (stage 62). The number of unidentifiable organs decreases constantly over this period of time and becomes zero at the oldest stages observed. Besides an absolute numerical increase in both types of organs both grow by increasing the number of cells per organ. Comparison with the development of the ampullary organs in catfish shows a striking similarity which suggest either similar functional constraints acting on both catfish and newts or can be interpreted as an indication of homology of both types of organs.

Electroreceptors and Direction Specific Arrangement in the Lateral Line System of Salamanders?

1981 ◽  
Vol 36 (5-6) ◽  
pp. 493-496 ◽  
Author(s):  
Bernd Fritzsch
Keyword(s):  
Lateral Line ◽  
Fiber Bundles ◽  
Sensory Cells ◽  
Lateral Line System ◽  
Line System ◽  
Lateral Line Organ ◽  
Posterior Lateral Line ◽  
Afferent Fibers ◽  
Lateral Line Afferents ◽  
Line Organ

Abstract The arrangement of the lateral line afferents of salamanders as revealed by transganglionic staining with horse­ radish peroxidase is described. Each lateral line organ is supplied by two fibers only. In the medulla these two afferent fibers run in separate fiber bundles. It is suggested, that only those fibers contacting lateral line sensory cells with the same polarity form together one bundle. Bundles formed by anterior or posterior lateral line afferents are also clearly separated. Beside the lateral line organs smaller pit organs are described. These organs are supplied by one afferent only which reveals an arrangement in the medulla different from that of the lateral line afferents. Based on anatomical facts, these small pit organs are considered to be electroreceptors. Centrifugally projecting neurons, most probably efferents, are described in the medulla.

scholarly journals Localization of Neurotrophin Specific Trk Receptors in Mechanosensory Systems of Killifish (Nothobranchius guentheri)

2021 ◽  
Vol 22 (19) ◽  
pp. 10411
Author(s):  
Marialuisa Aragona ◽  
Caterina Porcino ◽  
Maria Cristina Guerrera ◽  
Giuseppe Montalbano ◽  
Maria Levanti ◽  
...  
Keyword(s):  
Inner Ear ◽  
Hair Cells ◽  
S100 Protein ◽  
Sensory Systems ◽  
Sensory Cells ◽  
Lateral Line System ◽  
Suitable Model ◽  
Trk Receptors ◽  
Line System ◽  
Nothobranchius Guentheri

Neurotrophins (NTs) and their signal-transducing Trk receptors play a crucial role in the development and maintenance of specific neuronal subpopulations in nervous and sensory systems. NTs are supposed to regulate two sensory systems in fish, the inner ear and the lateral line system (LLS). The latter is one of the major mechanosensory systems in fish. Considering that annual fishes of the genus Nothobranchius, with their short life expectancy, have become a suitable model for aging studies and that the occurrence and distribution of neurotrophin Trk receptors have never been investigated in the inner ear and LLS of killifish (Nothobranchius guentheri), our study aimed to investigate the localization of neurotrophin-specific Trk receptors in mechanosensory systems of N. guentheri. For histological and immunohistochemical analysis, adult specimens of N. guentheri were processed using antibodies against Trk receptors and S100 protein. An intense immunoreaction for TrkA and TrkC was found in the sensory cells of the inner ear as well as in the hair cells of LLS. Moreover, also the neurons localized in the acoustic ganglia displayed a specific immunoreaction for all Trk receptors (TrkA, B, and C) analyzed. Taken together, our results demonstrate, for the first time, that neurotrophins and their specific receptors could play a pivotal role in the biology of the sensory cells of the inner ear and LLS of N. guentheri and might also be involved in the hair cells regeneration process in normal and aged conditions.

Mechanoreceptors for near-field water displacements in crayfish

1976 ◽  
Vol 39 (4) ◽  
pp. 816-833 ◽  
Author(s):  
K. Wiese
Keyword(s):  
Near Field ◽  
Hair Shaft ◽  
The Body ◽  
Sensory Cells ◽  
Lateral Line System ◽  
Frequency Range ◽  
Behavioral Experiments ◽  
Orthogonal Direction ◽  
Line System ◽  
Morphological Studies

1. Mechanosensory hairs on the surface of the crayfish telson are dually innervated, one sensory cell responding to headward, the other to tailward deflection of the hair. The average conduction velocity of headward elements was 0.8 m/s (variance 0.08) and of tailward elements 1.2 m/s (variance 0.19). In a frequency range from 0.05 to 200 Hz, thresholds were lowest near 20 Hz: 0.08 mum (pp) for headward-sensitive and 0.1 mum (pp) for tailward-sensitive cells. 2. The receptors are displacement sensitive since thresholds are of the same order of magnitude over the frequency range 1-70 Hz when the hair is moved by a vibrating wire loop. With natural stimuli (surface waves), the velocity component of the particle movement (and consequently force) becomes influential. The coding of a broad range of stimulus intensities is aided by variations in mechanical properties of the hair. 3. Marked directionality (better than 4:1), in addition to the dual innervation, enhances vector detection. At least part of this characteristic stems from the hingelike articulation of the hair on the body surface: the hair can be moved easily 40 degrees tailward and 20 degrees headward, but must be forced in the orthogonal direction. Morphological studies indicate the presence of a double pivoted hinge, with rigid guides for movement of the hair shaft. Preliminary results of electron microscope examination show a clearly polarized arrangement of densely packed microtubules in the two dendrites; they appear interconnected in groups of two and three along a line parallel to the sensitivity plane of the receptor. 4. The 50-fold threshold difference between the results of behavioral experiments in lobsters (24) and the data for the individual receptors reported here may be due to improvement in signal-to-noise ratio by central nervous averaging of the input from an estimated 2 X 10(3) receptors (Procambarus), and/or to the kind of threshold criteria applied to individual receptor thresholds. As would be expected (35), the sensory cells of each directional class synapse with separate interneurons: in this way, the organism might employ differential microphones to reduce background noise. 5. The receptors are analogous to those of the lateral-line system in lower vertebrates in having receptors with sensitivities polarized by 180 degrees. These similarities suggest that in both cases monitoring of near field water displacements has proved in essential way of orienting in opaque waters.

scholarly journals Sox2 and Sox3 are essential for development and regeneration of the zebrafish lateral line

2019 ◽  
Author(s):  
Cristian A. Undurraga ◽  
Yunzi Gou ◽  
Pablo C. Sandoval ◽  
Viviana A. Nuñez ◽  
Miguel L. Allende ◽  
...  
Keyword(s):  
Stem Cells ◽  
Lateral Line ◽  
Hair Cells ◽  
Topological Analysis ◽  
Time Lapse ◽  
Cell Types ◽  
Lateral Line System ◽  
Loss Of Function ◽  
Supporting Cells ◽  
Line System

ABSTRACTThe recovery of injured or lost sensory neurons after trauma, disease or aging is a major scientific challenge. Upon hearing loss or balance disorder, regeneration of mechanosensory hair cells has been observed in fish, some amphibians and under special circumstances in birds, but is absent in adult mammals. In aquatic vertebrates, hair cells are not only present in the inner ear but also in neuromasts of the lateral line system. The zebrafish lateral line neuromast has an almost unlimited capacity to regenerate hair cells. This remarkable ability is possible due to the presence of neural stem/progenitor cells within neuromasts. In order to further characterize these stem cells, we use the expression of the neural progenitor markers Sox2 and Sox3, transgenic reporter lines, and morphological and topological analysis of the different cell types within the neuromast. We reveal new sub-populations of supporting cells, the sustentacular supporting cells and the neuromast stem cells. In addition, using loss-of-function and mutants of sox2 and sox3, we find that the combined activity of both genes is essential for lateral line development and regeneration. The capability of sox2/sox3 expressing stem cells to produce new hair cells, hair cell-precursors, and supporting cells after damage was analyzed in detail by time-lapse microscopy and immunofluorescence. We are able to provide evidence that sox2/3 expressing cells are the main contributors to the regenerated neuromast, and that their daughter cells are able to differentiate into most cell types of the neuromast.

scholarly journals Using light-sheet microscopy to study spontaneous activity in the developing lateral-line system

2021 ◽  
Author(s):  
Qiuxiang Zhang ◽  
Katie Kindt
Keyword(s):  
Spontaneous Activity ◽  
Lateral Line ◽  
Hair Cells ◽  
Light Sheet ◽  
Lateral Line System ◽  
Supporting Cells ◽  
Line System ◽  
Calcium Activity ◽  
Light Sheet Microscopy ◽  
Calcium Indicators

Hair cells are the sensory receptors in the auditory and vestibular systems of all vertebrates, and in the lateral-line system of aquatic vertebrates. During development, spontaneous activity in hair cells shapes the formation of these sensory systems. In auditory hair cells of mice, coordinated waves of spontaneous activity can be triggered by concomitant activity in nearby supporting cells. But in mammals, developing auditory and vestibular hair cells can also autonomously generate spontaneous events independent of supporting cell activity. To date, significant progress has been made studying spontaneous activity in the auditory and vestibular systems of mammals, in isolated cultures. The purpose of this work is to explore the zebrafish lateral-line system as a model to study and understand spontaneous activity in vivo. Our work applies genetically encoded calcium indicators along with light-sheet fluorescence microscopy to visualize spontaneous calcium activity in the developing lateral-line system. Consistent with our previous work, we show that spontaneous calcium activity is present in developing lateral-line hair cells. We now show that supporting cells that surround hair cells, and cholinergic efferent terminals that directly contact hair cells are also spontaneously active. Using two-color functional imaging we demonstrate that spontaneous activity in hair cells does not correlate with activity in either supporting cells or cholinergic terminals. We find that during lateral-line development, hair cells autonomously generate spontaneous events. Using localized calcium indicators, we show that within hair cells, spontaneous calcium activity occurs in two distinct domains-the mechanosensory bundle and the presynapse. Further, spontaneous activity in the mechanosensory bundle ultimately drives spontaneous calcium influx at the presynapse. Comprehensively, our results indicate that in developing lateral-line hair cells, autonomously generated spontaneous activity originates with spontaneous mechanosensory events. Overall, with robust spontaneous activity three different cell types, the developing lateral line is a rich model to study these activities in an intact sensory organ. Future work studying this model may further our understanding of these activities and their role in sensory system formation, function and regeneration.

The Development of the Lateral Line System in Plaice (Pleuronectes Platessa) and Turbot (Scophthalmus Maximus)

1986 ◽  
Vol 66 (3) ◽  
pp. 683-693 ◽  
Author(s):  
D. A. Neave
Keyword(s):  
Lateral Line ◽  
Scophthalmus Maximus ◽  
Sensory Cells ◽  
Lateral Line System ◽  
Blind Side ◽  
Canal System ◽  
Line System ◽  
Pleuronectes Platessa ◽  
Body Regions ◽  
Turbot Scophthalmus Maximus

The distribution of free neuromasts and the formation of the lateral line canals are described for two species of flatfish (plaice, Pleuronectes platessa L., and turbot, Scophthalmus maximus L.) during development from the bilaterally symmetrical larva to the bilaterally asymmetrical adult. On hatching plaice have three free neuromasts per side compared with six in turbot. After feeding is established plaice have 40–60/side compared with 20–25 in turbot. During development the ‘hillock’ of sensory cells increases in size and the cupulae grow in length. Canal formation starts later in plaice than in turbot. During metamorphosis the canal system becomes more concentrated in the upper (eyed) side of both species, but lateral line canals occur both on the head and body regions of the blind side. In plaice the tubes leading from the canals to the surface have typically one pore/tube, whereas in turbot there is much branching with 8–10 pores/tube.

scholarly journals Insights into electrosensory organ development, physiology and evolution from a lateral line-enriched transcriptome

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Melinda S Modrell ◽  
Mike Lyne ◽  
Adrian R Carr ◽  
Harold H Zakon ◽  
David Buckley ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Hair Cell ◽  
Lateral Line ◽  
Glutamate Release ◽  
Cell Types ◽  
Lateral Line System ◽  
Organ Development ◽  
Line System ◽  
Evolutionary Diversification ◽  
Ampullary Organ

The anamniote lateral line system, comprising mechanosensory neuromasts and electrosensory ampullary organs, is a useful model for investigating the developmental and evolutionary diversification of different organs and cell types. Zebrafish neuromast development is increasingly well understood, but neither zebrafish nor Xenopus is electroreceptive and our molecular understanding of ampullary organ development is rudimentary. We have used RNA-seq to generate a lateral line-enriched gene-set from late-larval paddlefish (Polyodon spathula). Validation of a subset reveals expression in developing ampullary organs of transcription factor genes critical for hair cell development, and genes essential for glutamate release at hair cell ribbon synapses, suggesting close developmental, physiological and evolutionary links between non-teleost electroreceptors and hair cells. We identify an ampullary organ-specific proneural transcription factor, and candidates for the voltage-sensing L-type Cav channel and rectifying Kv channel predicted from skate (cartilaginous fish) ampullary organ electrophysiology. Overall, our results illuminate ampullary organ development, physiology and evolution.

Ultrastructure of superficial neuromasts in the mottled sculpin, Cottus bairdi

1989 ◽  
Vol 47 ◽  
pp. 958-959
Author(s):  
W.R. Jones ◽  
S. Coombs ◽  
J. Janssen
Keyword(s):  
Hair Cells ◽  
Lateral Line System ◽  
Electron Microscopic ◽  
Line System ◽  
Dense Cores ◽  
Sensory Hair Cells ◽  
Cytoplasmic Vesicles ◽  
Cottus Bairdi ◽  
Mottled Sculpin ◽  
Upper Third

The lateral line system of the mottled sculpin, like that of most bony fish, has both canal (CNM) and superficial (SNM) sensory end organs, neuromasts, which are distributed on the head and trunk in discrete, readily identifiable groupings (Fig. 1). CNM and SNM differ grossly in location and in overall size and shape. The former are located in subdermal canals and are larger and asymmetric in shape, The latter are located directly on the surface of the skin and are much smaller and more symmetrical It has been suggested that the two may differ at a more fundamental level in such functionally related parameters as extent of myelination of innervating fibers and the absence of efferent innervation in SNM. The present study addresses the validity of these last two features as distinguishing criteria by examining the structure of those SNM populations indicated in Fig. 1 at both the light and electron microscopic levels.All of the populations of SNM examined conform in general to previously published descriptions, consisting of a neuroepithelium composed of sensory hair cells, support cells and mantle cells, Several significant differences from these accounts have, however, emerged. Firstly, the structural composition of the innervating fibers is heterogeneous with respect to the extent of myelination. All SNM groups, with the possible exception of the TRrs and CFLs, possess both myelinated and unmyelinated fibers within the neuroepithelium proper (Fig. 2), just as do CNM. The extent of myelina- tion is quite variable, with some fibers sheath terminating just before crossing the neuroepithelial basal lamina, some just after and a few retaining their myelination all the way to the base of the hair cells in the upper third of the neuroepithelium. Secondly, all SNMs possess fibers that may, on the basis of ultrastructural criteria, be identified as efferent. Such fibers contained numerous cytoplasmic vesicles, both clear and with dense cores. In regions where such fibers closely apposed hair cells, subsynaptic cisternae were observed in the hair cell (Fig. 3).

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