Hair cells of different shapes and their placement along the frog crista ampullaris

Guth, Paul S.; Fermin, César D.; Pantoja, M.; Edwards, Ryan; Norris, Charles H.

doi:10.1016/0378-5955(94)90288-7

Cited by 18 publications

(11 citation statements)

References 24 publications

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“…These distinct physiological properties correlate with different hair bundle morphologies and different locations in the utricular macula (Baird 1994a,b;Baird and Lewis 1986;Lewis et al 1982). Similar morphological differences exist among the hair cells in the semicircular canal cristae (Baird and Lewis 1986;Gioglio et al 1995;Guth et al 1994; Lewis and Li 1975;Myers and Lewis 1990) and are associated with distinct micromechanics of the hair bundles (Flock and Orman 1983). Assuming that these morphological variations reflect the same differences in physiological properties as in the utricular macula, the segregation of vestibular hair cells according to their frequency sensitivity and response dynamics is likely to be a general property of all labyrinthine end organs.…”

Section: Introductionmentioning

confidence: 89%

“…These different hair cells would be best suited to code either tonic (nonadapting cells) or phasic (adapting cells) components of head movements (Baird 1994a,b). Assuming that similar morphological differences among canal as among macular hair cells, respectively, (Baird and Lewis 1986;Gioglio et al 1995;Guth et al 1994;Lewis and Li 1975;Myers and Lewis 1990) are paralleled by similar differences in physiological properties, a general functional segregation of hair cells in all labyrinthine end organs is likely.…”

Section: Parallel Frequency-tuned Channels Underlying Vestibuloocularmentioning

confidence: 99%

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Second-Order Vestibular Neurons Form Separate Populations With Different Membrane and Discharge Properties

Straka

Beraneck²,

Rohregger³

et al. 2004

Journal of Neurophysiology

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Straka, H., M. Beraneck, M. Rohregger, L. E. Moore, P.-P, Vidal, and N. Vibert. Second-order vestibular neurons form separate populations with different membrane and discharge properties. J Neurophysiol 92: 845-861, 2004. First published March 24, 2004 10.1152/ jn.00107.2004. Membrane and discharge properties were determined in second-order vestibular neurons (2°VN) in the isolated brain of grass frogs. 2°VN were identified by monosynaptic excitatory postsynaptic potentials after separate electrical stimulation of the utricular nerve, the lagenar nerve, or individual semicircular canal nerves. 2°VN were classified as vestibulo-ocular or -spinal neurons by the presence of antidromic spikes evoked by electrical stimulation of the spinal cord or the oculomotor nuclei. Differences in passive membrane properties, spike shape, and discharge pattern in response to current steps and ramp-like currents allowed a differentiation of frog 2°VN into two separate, nonoverlapping types of vestibular neurons. A larger subgroup of 2°VN (78%) was characterized by brief, high-frequency bursts of up to five spikes and the absence of a subsequent continuous discharge in response to positive current steps. In contrast, the smaller subgroup of 2°VN (22%) exhibited a continuous discharge with moderate adaptation in response to positive current steps. The differences in the evoked spike discharge pattern were paralleled by differences in passive membrane properties and spike shapes. Despite these differences in membrane properties, both types, i.e., phasic and tonic 2°VN, occupied similar anatomical locations and displayed similar afferent and efferent connectivities. Differences in response dynamics of the two types of 2°VN match those of their pre-and postsynaptic neurons. The existence of distinct populations of 2°VN that differ in response dynamics but not in the spatial organization of their afferent inputs and efferent connectivity to motor targets suggests that frog 2°VN form one part of parallel vestibulomotor pathways.

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Section: Introductionmentioning

confidence: 89%

Section: Parallel Frequency-tuned Channels Underlying Vestibuloocularmentioning

confidence: 99%

Second-Order Vestibular Neurons Form Separate Populations With Different Membrane and Discharge Properties

Straka

Beraneck²,

Rohregger³

et al. 2004

Journal of Neurophysiology

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“…7B). Interestingly, cells in this subpopulation all displayed a rounded shape, similar to hair cells previously defined as pear-shaped localized to the intermediate zone of the crista ampullaris (Guth et al 1994b;Masetto et al 1994;Prigioni et al 1996). In Fig.…”

Section: Dmpp Response Does Not Occur In All Posterior Scc Hair Cellsmentioning

confidence: 98%

A Pharmacologically Distinct Nicotinic ACh Receptor Is Found in a Subset of Frog Semicircular Canal Hair Cells

Holt

Lioudyno

Guth

2003

Journal of Neurophysiology

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A pharmacologically distinct nicotinic ACh receptor is found in a subset of frog semicircular canal hair cells. J Neurophysiol 90: 1526 -1536, 2003; 10.1152/jn.00273.2002. Frog vestibular organs are endowed with a prominent cholinergic efferent innervation whose stimulation results in several different effects, thereby suggesting diversity in the expression of postsynaptic acetylcholine (ACh) receptors. The application of ACh can mimic efferent stimulation in producing both an inhibition and a facilitation of afferent discharge which are thought to be mediated by at least two distinct ACh receptors present on vestibular hair cells, i.e., ␣9-containing nicotinic receptors (␣9nAChR) and muscarinic receptors (mAChR), respectively. Using patch-clamp and multiunit vestibular afferent recordings, we demonstrate the presence of an additional excitatory hair cell nicotinic ACh receptor pharmacologically distinct from both ␣9nAChR and mAChR. In order of increasing potency, this distinct receptor was activated by ACh, carbachol, and particularly by the selective nicotinic agonist 1,1-dimethyl-4-phenyl-piperazinium (DMPP). This DMPP-sensitive nicotinic receptor (R DMPP ) was antagonized by the classic nicotinic antagonist d-tubocurarine, but refractory to strychnine, atropine, and propylbenzilylcholine mustard, at concentrations that completely block ␣9nAChR and/or mAChR. Activation of R DMPP on application of ACh or DMPP to a subpopulation of isolated posterior semicircular canal (SCC) hair cells resulted in a large depolarization (18.0 Ϯ 1.2 mV). The current underlying this depolarization was typically small (80.1 Ϯ 21.6 pA) and showed an inward rectification starting around Ϫ45 mV. Given their respective EC 50 s (47 nM vs. 20 M), R DMPP was nearly 400 times more sensitive to ACh than ␣9nAChR and thus responded to concentrations of ACh considered too low to be effective at stimulating ␣9nAChR. Despite this remarkable sensitivity, exogenous ACh readily stimulated the mAChR in the intact posterior SCC preparation but failed to activate R DMPP unless the acetylcholinesterase inhibitor physostigmine was present, or high concentrations of ACh were used (Ͼ3 mM). In frog, R DMPP most likely underlies the rapid excitatory response seen during efferent stimulation.

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“…The club-like cells were located only in the peripheral regions of the crista, the cylindrical cells both in the central and peripheral regions, and the pear-like cells only in the intermediate regions. The presence in the frog crista of hair cells having different shapes and distribution has been recently described by other authors (MASETTO et al, 1994;GUTH et al, 1994). In addition, our results indicate that the (HONRUBIA et al, 1989;MYERS and LEWIS, 1990), then the general concept that only type II hair cells are present in lower vertebrates (WERSALL et al, 1965) must be revised and a further subdivision must be introduced.…”

Section: Discussionmentioning

confidence: 54%

“…However, in frog crista epithelium, several authors (LEWIS and LI, 1975;HOUSLEY et al, 1989;MYERS and LEWIS, 1990;GUTH et al, 1994;MASETTO et al, 1994) have recently described more than one kind of hair cell, distinguishing these either according to their superficial morphological features, or to their shape. On the basis of these differences and of the pattern of afferent innervation (HoNRUBIA et al,1989;MYERS and LEWIS,1990), the crista epithelium of vertical canals has been divided into three regions: peripheral, central and intermediate.…”

mentioning

confidence: 99%

Morphological Features of Different Regions in Frog Crista Ampullaris(Rana esculenta).

Gioglio

Congiu

Quacci

et al. 1995

Archives of Histology and Cytology

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Hair cells of different shapes and their placement along the frog crista ampullaris

Cited by 18 publications

References 24 publications

Second-Order Vestibular Neurons Form Separate Populations With Different Membrane and Discharge Properties

Second-Order Vestibular Neurons Form Separate Populations With Different Membrane and Discharge Properties

A Pharmacologically Distinct Nicotinic ACh Receptor Is Found in a Subset of Frog Semicircular Canal Hair Cells

Morphological Features of Different Regions in Frog Crista Ampullaris(Rana esculenta).

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