ATP activates non‐selective cation channels and calcium release in inner hair cells of the guinea‐pig cochlea.

Sugasawa, Masashi; Eróstegui, Carlos; Blanchet, Christophe; Dulon, Didier

doi:10.1113/jphysiol.1996.sp021251

Cited by 69 publications

(36 citation statements)

References 22 publications

(33 reference statements)

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“…Type Ι SGNs (90-95% of SGNs) innervate IHCs and transmit signals from the cochlea to the cochlear nucleus, while type II SGNs (5-10% of SGNs) innervate OHCs. ATP has been reported to induce an elevation of the [Ca 2+ ] i in IHCs and type Ι SGNs [6][7][8][9]. ATP thus acts as a hair cell-afferent neurotransmitter or neuromodulator in the cochlea.…”

Section: Effects Of Glucocorticoids On the Atp-induced No And Ca 2+ Smentioning

confidence: 99%

“…The activation of ligand-gated ionotropic P2X receptors and G protein-coupled metabotropic P2Y receptors has been reported to induce an increase of [Ca 2+ ] i in Hensen's cells in the cochlea [6,11,13]. It has been shown that the NOcGMP-PKG pathway participates in the ATP-induced Ca 2+ signalling in supporting cells, such as Deiters' cells and Hensen's cells [116].…”

Section: Role Of No On the Atp-induced Ca 2+ Signalling In Supportingmentioning

confidence: 99%

“…ATP has been described as a neurotransmitter or a neuromodulator in auditory neurotransmission. ATP has been reported to induce an increase of intracellular Ca 2+ concentration ([Ca 2+ ] i ) in outer hair cells (OHCs) [4,5], inner hair cells (IHCs) [6][7][8], spiral ganglion neurons (SGNs) [9,10], and supporting cells [11][12][13]. These previous studies suggested that ATP may affect auditory neurotransmission by modulating [Ca 2+ ] i in the cochlear cells.…”

Section: Introductionmentioning

confidence: 99%

“…These previous studies suggested that ATP may affect auditory neurotransmission by modulating [Ca 2+ ] i in the cochlear cells. It has been shown that OHCs and IHCs possess both ligand-gated ionotropic P2X receptors and G proteincoupled metabotropic P2Y receptors [5,6,14]. The extensive distribution of P2X 2 receptor subunit expression in the guinea pig cochlea provides evidence for divergent roles for extracellular ATP acting via ATP-gated ion channels [14].…”

Section: Introductionmentioning

confidence: 99%

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Role of nitric oxide on purinergic signalling in the cochlea

Harada

2010

Purinergic Signalling

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In the inner ear, there is considerable evidence that extracellular adenosine 5′-triphosphate (ATP) plays an important role in auditory neurotransmission as a neurotransmitter or a neuromodulator, although the potential role of adenosine signalling in the modulation of auditory neurotransmission has also been reported. The activation of ligand-gated ionotropic P2X receptors and G proteincoupled metabotropic P2Y receptors has been reported to induce an increase of intracellular Ca 2+ concentration ([Ca 2+ ] i ) in inner hair cells (IHCs), outer hair cells (OHCs), spiral ganglion neurons (SGNs), and supporting cells in the cochlea. ATP may participate in auditory neurotransmission by modulating [Ca 2+ ] i in the cochlear cells. Recent studies showed that extracellular ATP induced nitric oxide (NO) production in IHCs, OHCs, and SGNs, which affects the ATP-induced Ca 2+ response via the NO-cGMP-PKG pathway in those cells by a feedback mechanism. A cross-talk between NO and ATP may therefore exist in the auditory signal transduction. In the present article, I review the role of NO on the ATP-induced Ca 2+ signalling in IHCs and OHCs. I also consider the possible role of NO in the ATP-induced Ca 2+ signalling in SGNs and supporting cells.

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Section: Effects Of Glucocorticoids On the Atp-induced No And Ca 2+ Smentioning

confidence: 99%

Section: Role Of No On the Atp-induced Ca 2+ Signalling In Supportingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Role of nitric oxide on purinergic signalling in the cochlea

Harada

2010

Purinergic Signalling

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“…In the cochlea, it has been reported that ATP can evoke inward currents and raise the intracellular Ca ++ concentration in the outer and inner hair cells, thereby modifying sound transduction and neurotransmission [10][11][12][13]. ATP can activate purinergic (P2) receptors to produce inward cationic currents [14,15].…”

Section: Introductionmentioning

confidence: 99%

ATP-mediated potassium recycling in the cochlear supporting cells

Zhu

Zhao

2010

Purinergic Signalling

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Gap junction-mediated K + recycling in the cochlear supporting cell has been proposed to play a critical role in hearing. However, how potassium ions enter into the supporting cells to recycle K + remains undetermined. In this paper, we report that ATP can mediate K + sinking to recycle K + in the cochlear supporting cells. We found that micromolar or submicromolar levels of ATP could evoke a K + -dependent inward current in the cochlear supporting cells. At negative membrane potentials and the resting membrane potential of −80 mV, the amplitude of the ATPevoked inward current demonstrated a linear relationship to the extracellular concentration of K + , increasing as the extracellular concentration of K + increased. The inward current also increased as the concentration of ATP was increased. In the absence of ATP, there was no evoked inward current for extracellular K + challenge in the cochlear supporting cells. The ATP-evoked inward current could be inhibited by ionotropic purinergic (P2X) receptor antagonists. Application of pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid (PPADS, 50 µM) or pre-incubation with an irreversible P2X7 antagonist oxidized ATP (oATP, 0.1 mM) completely abolished the ATP-evoked inward current at the negative membrane potential. ATP also evoked an inward current at cell depolarization, which could be inhibited by intracellular Cs + and eliminated by positive holding potentials. Our data indicate that ATP can activate P2X receptors to recycle K + in the cochlear supporting cells at the resting membrane potential under normal physiological and pathological conditions. This ATP-mediated K + recycling may play an important role in the maintenance of cochlear ionic homeostasis.

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Immunohistochemical localization of adenosine 5`-triphosphate-gated ion channel P2X2 receptor subunits in adult and developing rat cochlea

2000

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Substantial in vitro and in vivo data support a role for extracellular adenosine 5`‐triphosphate (ATP) and associated P2 receptors in cochlear function. However, the precise spatiotemporal distribution of the involved receptor protein(s) has not been determined. By using a specific antiserum and immunoperoxidase labeling, the tissue distribution of the P2X2 subunit of the ATP‐gated ion channel was investigated. Here, we describe the first extensive immunohistochemical mapping of P2X2 receptor subunits in the adult and developing rat cochlea. In the adult, immunoreactivity was observed in most cells bordering on the endolymphatic compartment (scala media), particularly in the supporting cells. Hair cells were not immunostained by the P2X2 antiserum, except for outer hair cell stereocilia. In addition, weak immunolabeling was observed in some spiral ganglion neurons. P2X2 receptor subunit protein expression during labyrinthine ontogeny was detected first on embryonic day 19 in the spiral ganglion and in associated nerve fibers extending to the inner hair cells. Immunostaining also was observed underneath outer hair cells, and, by postnatal day 6 (P6), intense immunolabeling was seen in the synaptic regions of both types of hair cell. Supporting cells of the sensory epithelium were labeled at P0. This labeling became most prominent from the onset of cochlear function (P8–P12). Conversely, expression in the vascular stria declined from this time. By P21, the pattern of immunolabeling was similar to that found in the adult. The localization and timing of P2X2 immunoreactivity suggest involvement of extracellular ATP and associated ATP‐gated ion channels in important physiological events, such as inner ear ontogeny, sound transduction, cochlear micromechanics, electrochemical homeostasis, and auditory neurotransmission. J. Comp. Neurol. 421:289–301, 2000. © 2000 Wiley‐Liss, Inc.

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ATP activates non‐selective cation channels and calcium release in inner hair cells of the guinea‐pig cochlea.

Cited by 69 publications

References 22 publications

Role of nitric oxide on purinergic signalling in the cochlea

Role of nitric oxide on purinergic signalling in the cochlea

ATP-mediated potassium recycling in the cochlear supporting cells

Immunohistochemical localization of adenosine 5`-triphosphate-gated ion channel P2X2 receptor subunits in adult and developing rat cochlea

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