Contribution of glutamate receptors to spontaneous and stimulus-evoked discharge in afferent fibers innervating hair cells of the Xenopus lateral line organ

1. The response of the epidermal lateral-line organ of Xenopus laevis to stimulation was studied by recording extracellular receptor potentials from the hair cells in single neuromasts in isolated preparations. One neuromast was stimulated by local, sinusoidal water movements induced by a glass sphere positioned at a short distance from the neuromast. 2. The amplitudes of the extracellular receptor potentials were proportional to the stimulus amplitude over a range of 20 dB. The phase of the extracellular receptor potentials with respect to water displacement was independent of the stimulus amplitude. 3. With large stimulus amplitude, and stimulus frequencies between 0.5 Hz and 2 Hz, the extracellular receptor potentials, and responses of single afferent nerve fibres, showed a phase lead of 1.2 π radians with respect to water displacement, i.e. they were almost in phase with water acceleration. 4. It is concluded that under conditions of stimulation with small-amplitude water movements, the hair cells respond to sensory hair displacement, whereas under conditions of stimulation with large-amplitude water movements they respond to sensory hair velocity.

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

Zeitschrift für Naturforschung C ◽

10.1515/znc-1981-5-628 ◽

1981 ◽

Vol 36 (5-6) ◽

pp. 493-496 ◽

Cited By ~ 20

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.

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Calcium-induced electron density in synaptic vesicles of afferent and efferent synapses on hair cells in the lateral line organ

Brain Research ◽

10.1016/0006-8993(77)90448-6 ◽

1977 ◽

Vol 121 (1) ◽

pp. 173-178 ◽

Cited By ~ 12

Author(s):

Gadi Benshalom ◽

A˚ke Flock

Keyword(s):

Electron Density ◽

Lateral Line ◽

Hair Cells ◽

Synaptic Vesicles ◽

Lateral Line Organ ◽

Line Organ

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The lhfpl5 ohnologs lhfpl5a and lhfpl5b are required for mechanotransduction in distinct populations of sensory hair cells in zebrafish

10.1101/793042 ◽

2019 ◽

Author(s):

Timothy Erickson ◽

Itallia V. Pacentine ◽

Alexandra Venuto ◽

Rachel Clemens ◽

Teresa Nicolson

Keyword(s):

Inner Ear ◽

Lateral Line ◽

Hair Cells ◽

Vestibular Function ◽

Fusion Partner ◽

Primary Role ◽

Mechanical Stimuli ◽

Vestibular Hair Cells ◽

Lateral Line Organ ◽

Line Organ

1AbstractHair cells sense and transmit auditory, vestibular, and hydrodynamic information by converting mechanical stimuli into electrical signals. This process of mechano-electrical transduction (MET) requires a mechanically-gated channel localized in the apical stereocilia of hair cells. In mice, lipoma HMGIC fusion partner-like 5 (LHFPL5) acts as an auxiliary subunit of the MET channel whose primary role is to correctly localize PCDH15 and TMC1 to the mechanotransduction complex. Zebrafish have two lhfpl5 genes (lhfpl5a and lhfpl5b), but their individual contributions to MET channel assembly and function have not been analyzed.Here we show that the zebrafish lhfpl5 genes are expressed in discrete populations of hair cells: lhfpl5a expression is restricted to auditory and vestibular hair cells in the inner ear, while lhfpl5b expression is specific to hair cells of the lateral line organ. Consequently, lhfpl5a mutants exhibit defects in auditory and vestibular function, while disruption of lhfpl5b affects hair cells only in the lateral line neuromasts. In contrast to previous reports in mice, localization of Tmc1 does not depend upon Lhfpl5 function in either the inner ear or lateral line organ. In both lhfpl5a and lhfpl5b mutants, GFP-tagged Tmc1 and Tmc2b proteins still localize to the stereocilia of hair cells. Using a stably integrated GFP-Lhfpl5a transgene, we show that the tip link cadherins Pcdh15a and Cdh23, along with the Myo7aa motor protein, are required for correct Lhfpl5a localization at the tips of stereocilia. Our work corroborates the evolutionarily conserved co-dependence between Lhfpl5 and Pcdh15, but also reveals novel requirements for Cdh23 and Myo7aa to correctly localize Lhfpl5a. In addition, our data suggest that targeting of Tmc1 and Tmc2b proteins to stereocilia in zebrafish hair cells occurs independently of Lhfpl5 proteins.

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Polydimethylsiloxane (PDMS) Waveguide Sensor Detecting Fluid Flow Velocity by Mimicking the Fish Lateral Line Organ

Proceedings ◽

10.3390/proceedings2130885 ◽

2018 ◽

Vol 2 (13) ◽

pp. 885

Author(s):

Bianca Wiesmayr ◽

Michael Krieger ◽

Werner Baumgartner ◽

Anna T. Stadler

Keyword(s):

Fluid Flow ◽

Lateral Line ◽

Hair Cells ◽

Water Movement ◽

Neural Signals ◽

Lateral Line Organ ◽

Fluid Flow Velocity ◽

Light Loss ◽

Line Organ ◽

Waveguide Sensor

Accurate measurement of fluid flow velocities is challenging but essential in many disciplines. Inspiration of possible measurement methods can come from nature, for example from the lateral line organ of fish, which is comprised of hair cells embedded in a gelatinous cupula. When the cupula is deflected by water movement, the hair cells initiate neural signals that generate an accurate image of the fish’s surroundings. We built a flow sensor mimicking a hair cell, yet coupled it with an optical detection method. Fluid flow bends the waveguide; this leads to a measurable light loss that depends linearly on the waveguide deflection.

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