Auditory sensory cells in hawkmoths: identification, physiology and structure

1999 ◽  
Vol 202 (12) ◽  
pp. 1579-1587 ◽  
Author(s):  
M.C. Göpfert ◽  
L.T. Wasserthal
Keyword(s):  
Neuronal Activity ◽  
Sensory Cell ◽  
Sensory Organ ◽  
Sensory Cells ◽  
Chordotonal Organ ◽  
Auditory Function ◽  
Sensory Structure ◽  
Ultrasonic Stimulation ◽  
Afferent Response

The labral pilifers are thought to contain auditory sensory cells in hawkmoths of two distantly related subtribes, the Choerocampina and the Acherontiina. We identified and analysed these cells using neurophysiological and neuroanatomical techniques. In the death's head hawkmoth Acherontia atropos, we found that the labral nerve carries the auditory afferent responses of a single auditory unit. This unit responds to ultrasonic stimulation with minimum thresholds of 49–57 dB SPL around 25 kHz. Ablation experiments and analyses of the neuronal activity in different regions of the pilifer revealed that the auditory afferent response originates in the basal pilifer region. The sensory organ was identified as a chordotonal organ that attaches to the base of the pilifer. This organ is the only sensory structure in the basal pilifer region and consists of a single mononematic scolopidium and a single sensory cell. In Choerocampina, a homologous scolopidium was also found and is probably the only sensory structure of the pilifer that might serve an auditory function. Since a pilifer chordotonal organ with only a single scolopidium has also been detected in a non-hearing hawkmoth species, hearing in the distantly related choerocampine and acherontiine hawkmoths presumably evolved from a single proprioceptive mechanoreceptor cell that is present in all hawkmoths.

scholarly journals Oral Antioxidant Vitamins and Magnesium Limit Noise-Induced Hearing Loss by Promoting Sensory Hair Cell Survival: Role of Antioxidant Enzymes and Apoptosis Genes

Antioxidants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1177
Author(s):  
Juan C. Alvarado ◽  
Verónica Fuentes-Santamaría ◽  
Pedro Melgar-Rojas ◽  
María C. Gabaldón-Ull ◽  
José J. Cabanes-Sanchis ◽  
...  
Keyword(s):  
Cell Death ◽  
Hearing Loss ◽  
Antioxidant Enzymes ◽  
Oral Administration ◽  
Hair Cell ◽  
Cell Survival ◽  
Sensory Cell ◽  
Auditory Function ◽  
Sensory Hair ◽  
Sensory Hair Cell

Noise induces oxidative stress in the cochlea followed by sensory cell death and hearing loss. The proof of principle that injections of antioxidant vitamins and Mg2+ prevent noise-induced hearing loss (NIHL) has been established. However, effectiveness of oral administration remains controversial and otoprotection mechanisms are unclear. Using auditory evoked potentials, quantitative PCR, and immunocytochemistry, we explored effects of oral administration of vitamins A, C, E, and Mg2+ (ACEMg) on auditory function and sensory cell survival following NIHL in rats. Oral ACEMg reduced auditory thresholds shifts after NIHL. Improved auditory function correlated with increased survival of sensory outer hair cells. In parallel, oral ACEMg modulated the expression timeline of antioxidant enzymes in the cochlea after NIHL. There was increased expression of glutathione peroxidase-1 and catalase at 1 and 10 days, respectively. Also, pro-apoptotic caspase-3 and Bax levels were diminished in ACEMg-treated rats, at 10 and 30 days, respectively, following noise overstimulation, whereas, at day 10 after noise exposure, the levels of anti-apoptotic Bcl-2, were significantly increased. Therefore, oral ACEMg improves auditory function by limiting sensory hair cell death in the auditory receptor following NIHL. Regulation of the expression of antioxidant enzymes and apoptosis-related proteins in cochlear structures is involved in such an otoprotective mechanism.

Ultrastructure of a sensillum associated with the pharynx of the cockroach Periplaneta americana

1996 ◽  
Vol 74 (11) ◽  
pp. 1999-2008
Author(s):  
R. Gary Chiang ◽  
K. G. Davey
Keyword(s):  
Electron Microscopy ◽  
Cell Body ◽  
Extracellular Space ◽  
Direct Contact ◽  
Periplaneta Americana ◽  
Sensory Cell ◽  
Sensory Cells ◽  
Osmotic Concentration ◽  
Sensory Cilia ◽  
Ultrathin Sections

A sensillum associated with the pharynx of the cockroach Periplaneta americana was examined in serial ultrathin sections using electron microscopy. This sensillum consisted of a group of 10–20 similar sensillar subunits. Each sensillar subunit possessed one 60- to 70-μm long dendritic sheath that made direct contact with the cuticle. The dendritic sheath enclosed 3–5 sensory cilia arising from 3–5 sensory cells located in a cluster approximately 30 μm proximal to the base of the sheath. Between the sensory cell body and the base of the sheath the dendrites were wrapped by the sheath-forming cell. Before entering the dendritic sheath itself, the dendrites crossed through an extracellular space, the ciliary sinus. No cuticular specializations, such as a well-defined sensory hair or pore, were observed. The structure of this sensillum suggests that it responds poorly to mechanical distortion of its surroundings. This characteristic supports the hypothesis that this sensillum measures the osmotic concentration of the ingested food.

Photoinactivation of the giant neuropil glial cells in the leech Hirudo medicinalis: effects on neuronal activity and synaptic transmission

1996 ◽  
Vol 76 (5) ◽  
pp. 2861-2871 ◽  
Author(s):  
J. Schmidt ◽  
J. W. Deitmer
Keyword(s):  
Synaptic Transmission ◽  
Glial Cells ◽  
Neuronal Activity ◽  
Lucifer Yellow ◽  
Hirudo Medicinalis ◽  
Membrane Properties ◽  
Sensory Cells ◽  
Chemical Synapse ◽  
Segmental Ganglion ◽  
Retzius Cells

1. We studied the effects of photoinactivation of neuropil glial (NG) cells of the leech Hirudo medicinalis on neuronal activity and synaptic transmission. Each segmental ganglion contains two of these giant glial cells, which are electrically and dye coupled. 2. One of the two NG cells in an isolated segmental ganglion was filled with the dye Lucifer yellow (LY). Subsequent irradiation of the ganglion with laser light (440 nm) to photolyze LY caused irreversible depolarization of both NG cells. The NG cells that were filled with LY depolarized from -73 +/- 1.1 (SE) mV to -22 +/- 2.4 mV within 25 +/- 2.8 min of continuous irradiation (n = 22). The other NG cell, which was not directly filled with LY, depolarized with some delay. 3. Photoinactivation of the NG cells caused an irreversible depolarization of Retzius neurons and noxious (N) sensory cells by a mean of 14 mV (n = 36) and 9 mV (n = 24), respectively. In addition, the input resistance was reduced by 54% in Retzius cells and by 34% in N cells. Spikes could not be evoked in Retzius cells after the inactivation of the NG cells, either by intracellular current injection or by electrical nerve stimulation. Similarly, anterior pagoda neurons, annulus erector neurons, and the excitor neurons of the ventrolateral circular muscles became inexcitable. However, N cells, heart interneurons, and most of the heart motor neurons, touch cells, and pressure cells could still generate spontaneous or evoked action potentials. 4. Photoinactivation of the NG cells impaired the electrical connection between the two Retzius neurons. The electrical coupling was completely eliminated in six of eight cell pairs and reduced by 66% in two others. 5. Photoinactivation of the NG cells in the 3rd and 4th segmental ganglion caused a complete block of the chemical synapse between reciprocal inhibitory heart interneurons in these ganglia; the bursting rhythm either stopped or changed to a tonic activity, whereas inhibitory postsynaptic potentials could not be recorded in either heart interneuron anymore. 6. Laser irradiation alone had no effect on neuronal activity and synaptic transmission. Addition of glutathione (10 mM) and ascorbic acid (10 mM) to the saline to bind extracellular radicals that might be produced by the irradiation did not suppress the effects caused by photoinactivation of NG cells. 7. Elevation of bath K+ concentration to 12 mM, acidification of the saline to pH 5.5, and alkalinization to pH 8.5 for 6 min each did not mimick the effects on membrane properties of Retzius cells as produced by inactivation of NG cells. The results suggest some role of glial cells in the maintenance of neuronal activity and electrical and chemical synaptic transmission.

Lineage, cell polarity and inscuteable function in the peripheral nervous system of the Drosophila embryo

Development ◽  
2001 ◽  
Vol 128 (5) ◽  
pp. 631-643 ◽  
Author(s):  
V. Orgogozo ◽  
F. Schweisguth ◽  
Y. Bellaiche
Keyword(s):  
Nervous System ◽  
Peripheral Nervous System ◽  
Cell Polarity ◽  
Asymmetric Cell Division ◽  
Drosophila Embryo ◽  
Sensory Organ ◽  
Chordotonal Organ ◽  
Cell Divisions ◽  
Ideal System ◽  
Asymmetric Divisions

The stereotyped pattern of the Drosophila embryonic peripheral nervous system (PNS) makes it an ideal system to use to identify mutations affecting cell polarity during asymmetric cell division. However, the characterisation of such mutations requires a detailed description of the polarity of the asymmetric divisions in the sensory organ lineages. We describe the pattern of cell divisions generating the vp1-vp4a mono-innervated external sense (es) organs. Each sensory organ precursor (SOP) cell follows a series of four asymmetric cell divisions that generate the four es organs cells (the socket, shaft, sheath cells and the es neurone) together with one multidendritic (md) neurone. This lineage is distinct from any of the previously proposed es lineages. Strikingly, the stereotyped pattern of cell divisions in this lineage is identical to those described for the embryonic chordotonal organ lineage and for the adult thoracic bristle lineage. Our analysis reveals that the vp2-vp4a SOP cells divide with a planar polarity to generate a dorsal pIIa cell and a ventral pIIb cell. The pIIb cell next divides with an apical-basal polarity to generate a basal daughter cell that differentiates as an md neurone. We found that Inscuteable specifically accumulated at the apical pole of the dividing pIIb cell and regulated the polarity of the pIIb division. This study establishes for the first time the function of Inscuteable in the PNS, and provides the basis for studying the mechanisms controlling planar and apical-basal cell polarities in the embryonic sensory organ lineages.

scholarly journals FUNCTIONAL SPECIALIZATION OF THE SCOLOPARIA OF THE FEMORAL CHORDOTONAL ORGAN IN STICK INSECTS

1992 ◽  
Vol 173 (1) ◽  
pp. 91-108 ◽  
Author(s):  
R. Kittmann ◽  
J. Schmitz
Keyword(s):  
Stick Insect ◽  
Sensory Cells ◽  
Chordotonal Organ ◽  
Functional Specialization ◽  
Control Loop ◽  
Sense Organs ◽  
Stick Insects ◽  
Extensor Motoneurones

The femoral chordotonal organ (fCO), one of the largest proprioceptive sense organs in the leg of the stick insect, is important for the control of the femur-tibia joint during standing and walking. It consists of a ventral scoloparium with about 80 sensory cells and a dorsal scoloparium with about 420 sensory cells. The present study examines the function of these scoloparia in the femur-tibia control loop. Both scoloparia were stimulated independently and the responses in the extensor tibiae motoneurones were recorded extra- and intracellularly. The ventral scoloparium, which is the smaller of the two, functions as the transducer of the femur-tibia control loop. Its sensory cells can generate the known resistance reflexes. The dorsal scoloparium serves no function in the femur-tibia control loop and its stimulation elicited no or only minor reactions in the extensor motoneurones. A comparison with other insect leg proprioceptors shows that a morphological subdivision of these organs often indicates a functional specialization.

The fine structure of crustacean proprioceptors I. The chordotonal organs in the legs of the shore crab, Carcinus maenas

1962 ◽  
Vol 245 (725) ◽  
pp. 291-324 ◽  
Keyword(s):  
Fine Structure ◽  
Connective Tissue ◽  
Sensory Cell ◽  
Light And Electron Microscopy ◽  
Carcinus Maenas ◽  
Sensory Nerve ◽  
Shore Crab ◽  
Structural Basis ◽  
Sensory Cells ◽  
Axial Filament

In the walking legs of the shore crab, Carcinus maenas , is a series of chordotonal organs. Each organ consists of a strand of elastic connective tissue in which are embedded scolopidia. The anatomy and histology of the organs in the coxopodite-basipodite, meropodite-carpopodite, carpopodite-propodite and propodite-dactylopodite joints are described in detail, as seen by light and electron microscopy. The organs are hereafter referred to by the initial letters of the leg segments with which they are associated. The CB organ runs from a projection near the dorsal hinge of the coxa to the dorsal rim of the basipodite. MC1 runs from the side of the tendon of the ‘accessory flexor’ muscle to two attachments on the preaxial wall of the meropodite. MC2 runs from the adductor tendon to the preaxial wall of the carpopodite. CP1 runs from the productor tendon to two ventral attachments on the carpopodite. CP2 runs from the reductor tendon to the floor of the propodite. PD runs from the adductor tendon to the postaxial wall of the dactylopodite. The scolopidia have a tube distal to the scolopale, into which are inserted the ends of the distal processes of bipolar sensory nerve cells. The tube is an extracellular organ apparently formed by the cell that contains the scolopale as an intracellular organ. Each scolopidium has associated with it two sensory cells, whose cell bodies lie in, on or near the connective tissue strands. In CB the sensory cells of a pair are similar to one another (isodynal scolopidia); in the other organs the two cells are dissimilar in their fine structure (heterodynal scolopidia). The difference, in the heterodynal scolopidia, consists in the presence or absence of a part of the distal process, the ciliary segment, which has nine double peripheral filaments regularly spaced, and in the precise form of the distal end of the axial filament. In all scolopidia, the two distal processes of the sensory cells are separated by intrusions of the sheath cells or of the scolopale cell, except for an area near the base of the scolopale where their cell membranes are in apposition; this area is referred to as the ephapse. At the level of the base of the scolopale the distal processes each contain an axial filament, which shows transverse striations, and there are attachment plaques between the distal processes and the scolopale cell. Distal to this level, each sensory cell contains a centrosome. Distal to the centrosome, the distal processes, which cross the scolopale space to end in the tube, can be divided into the following regions: a ciliary segment (where it occurs), a paraciliary segment characterized by nine double peripheral filaments less regularly arranged than in the ciliary segment, and a terminal segment characterized by numerous single microtubules. It is suggested that in each scolopidium one sensory cell responds to extension of the strand, and one to its shortening. This might account for the unidirectional responses observed in the organs. No structural basis for the observed differentiation of the sensory cells into ‘position’ and ‘movement’ receptors could be found.

Drosophila Hören: Mechanismen und Gene

e-Neuroforum ◽  
2014 ◽  
Vol 20 (3) ◽  
Author(s):  
Maike Kittelmann ◽  
Martin Göpfert
Keyword(s):  
Drosophila Melanogaster ◽  
Transcription Factors ◽  
Ion Channels ◽  
Hair Cells ◽  
Motor Proteins ◽  
Fruit Fly ◽  
Sensory Organ ◽  
Sensory Cells ◽  
Mechanical Vibrations ◽  
Signalling Cascades

AbstractDrosophila hearing: mechanisms and genes.The fruit fly Drosophila melanogaster communicates acoustically and hears with its antennae. Fundamental aspects of hearing can be studied in these antennal ears. Their auditory sensory cells are evolutionarily related with vertebrate hair cells and are developmentally specified by homologous transcription factors. Like vertebrate hair cells, Drosophila auditory sensory cells are also motile and actively amplify the mechanical vibrations that they transduce. This transduction and amplification rely on the interplay between mechanically activated ion channels and motor proteins, whose movement impacts on the macroscopic performance of the ear. First molecular trans­ducer components have been identified and various auditory relevant proteins have been described. Several of these proteins are conserved components of cilia, putting forward the fly’s ear as a model for human ciliopathies. Also the evolution of sensory signalling cascades can be studied using the fly’s ear as the fly employs key Chemo-and Photoreceptor proteins to hear. Evidence is also accumulating that the fly’s ear is a multifunctional sensory organ that, in addition to mediating hearing, serves the detection of wind and gravity and, presumably, temperature.

Functional Group Recognition of Pheromone Molecules by Sensory Cells of Antheraea polyphemus and Antheraea pernyi (Lepidoptera: Saturniidae)

1987 ◽  
Vol 42 (4) ◽  
pp. 435-441 ◽  
Author(s):  
H. J. Bestmann ◽  
Wu Cai-Hong ◽  
B. Döhla ◽  
Li-Kedong ◽  
K. E. Kaissling
Keyword(s):  
Functional Group ◽  
Sensory Cell ◽  
Receptor Cell ◽  
Sensory Cells ◽  
Signal Molecule ◽  
Chemical Structures ◽  
Dendritic Membrane ◽  
Pheromone Components ◽  
Electronic Character ◽  
End Group

Abstract The pheromone components of A. polyphemus, (6 E, 11 Z)-6 ,11-hexadecadienyl acetate and (6 E, 11 Z)-6 ,11-hexadecadienal, both effective also in A. pernyi, were synthetically varied in their chemical structures and these compounds electrophysiologically tested in single cell recordings. It appeared that for the interaction between the signal molecule and the receptor region at the dendritic membrane of the receptor cell the electronic character of the functional end group (acetate or aldehyde) of the stimulus molecule is important. The excitation of the sensory cell also depends on the chain length.

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