GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Developmental Regulation of Nicotinic Synapses on Cochlear Inner Hair Cells
    Society for Neuroscience ; 2004
    In:  The Journal of Neuroscience Vol. 24, No. 36 ( 2004-09-08), p. 7814-7820
    Details
    In: The Journal of Neuroscience, Society for Neuroscience, Vol. 24, No. 36 ( 2004-09-08), p. 7814-7820
    Abstract: In the mature cochlea, inner hair cells (IHCs) transduce acoustic signals into receptor potentials, communicating to the brain by synaptic contacts with afferent fibers. Before the onset of hearing, a transient efferent innervation is found on IHCs, mediated by a nicotinic cholinergic receptor that may contain both α9 and α10 subunits. Calcium influx through that receptor activates calcium-dependent (SK2-containing) potassium channels. This inhibitory synapse is thought to disappear after the onset of hearing [after postnatal day 12 (P12)]. We documented this developmental transition using whole-cell recordings from IHCs in apical turns of the rat organ of Corti. Acetylcholine elicited ionic currents in 88-100% of IHCs between P3 and P14, but in only 1 of 11 IHCs at P16-P22. Potassium depolarization of efferent terminals caused IPSCs in 67% of IHCs at P3, in 100% at P7-P9, in 93% at P10-P12, but in only 40% at P13-P14 and in none of the IHCs tested between P16 and P22. Earlier work had shown by in situ hybridization that α9 mRNA is expressed in adult IHCs but thatα10 mRNA disappears after the onset of hearing. In the present study, antibodies toα10 and to the associated calcium-dependent (SK2) potassium channel showed a similar developmental loss. The correlated expression of these gene products with functional innervation suggests that Alpha10 and SK2 , but not Alpha9, are regulated by synaptic activity. Furthermore, this developmental knock-out of α10, but not α9, supports the hypothesis that functional nicotinic acetylcholine receptors in hair cells are heteromers containing both these subunits.
    Type of Medium: Online Resource
    ISSN: 0270-6474 , 1529-2401
    URL: Article
    DOI: 10.1523/JNEUROSCI.2102-04.2004
    Language: English
    Publisher: Society for Neuroscience
    Publication Date: 2004
    detail.hit.zdb_id: 1475274-8
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    The α10 nicotinic acetylcholine receptor subunit is required for normal synaptic function and integrity of the olivocochlear system
    Proceedings of the National Academy of Sciences ; 2007
    In:  Proceedings of the National Academy of Sciences Vol. 104, No. 51 ( 2007-12-18), p. 20594-20599
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 104, No. 51 ( 2007-12-18), p. 20594-20599
    Abstract: Although homomeric channels assembled from the α9 nicotinic acetylcholine receptor (nAChR) subunit are functional in vitro , electrophysiological, anatomical, and molecular data suggest that native cholinergic olivocochlear function is mediated via heteromeric nAChRs composed of both α9 and α10 subunits. To gain insight into α10 subunit function in vivo , we examined olivo cochlear innervation and function in α 10 null-mutant mice. Electrophysiological recordings from postnatal (P) days P8–9 inner hair cells revealed ACh-gated currents in α 10 +/+ and α 10 +/− mice, with no detectable responses to ACh in α 10 −/− mice. In contrast, a proportion of α 10 −/− outer hair cells showed small ACh-evoked currents. In α 10 −/− mutant mice, olivocochlear fiber stimulation failed to suppress distortion products, suggesting that the residual α9 homomeric nAChRs expressed by outer hair cells are unable to transduce efferent signals in vivo . Finally, α 10 −/− mice exhibit both an abnormal olivocochlear morphology and innervation to outer hair cells and a highly disorganized efferent innervation to the inner hair cell region. Our results demonstrate that α 9 −/− and α 10 −/− mice have overlapping but nonidentical phenotypes. Moreover, α10 nAChR subunits are required for normal olivocochlear activity because α9 homomeric nAChRs do not support maintenance of normal olivocochlear innervation or function in α 10 −/− mutant mice.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.0708545105
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2007
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    α10: A determinant of nicotinic cholinergic receptor function in mammalian vestibular and cochlear mechanosensory hair cells
    Proceedings of the National Academy of Sciences ; 2001
    In:  Proceedings of the National Academy of Sciences Vol. 98, No. 6 ( 2001-03-13), p. 3501-3506
    Details
    In: Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 98, No. 6 ( 2001-03-13), p. 3501-3506
    Abstract: We report the cloning and characterization of rat α10, a previously unidentified member of the nicotinic acetylcholine receptor (nAChR) subunit gene family. The protein encoded by the α10 nAChR subunit gene is most similar to the rat α9 nAChR, and both α9 and α10 subunit genes are transcribed in adult rat mechanosensory hair cells. Injection of Xenopus laevis oocytes with α10 cRNA alone or in pairwise combinations with either α2-α6 or β2-β4 subunit cRNAs yielded no detectable ACh-gated currents. However, coinjection of α9 and α10 cRNAs resulted in the appearance of an unusual nAChR subtype. Compared with homomeric α9 channels, the α9α10 nAChR subtype displays faster and more extensive agonist-mediated desensitization, a distinct current–voltage relationship, and a biphasic response to changes in extracellular Ca 2+ ions. The pharmacological profiles of homomeric α9 and heteromeric α9α10 nAChRs are essentially indistinguishable and closely resemble those reported for endogenous cholinergic eceptors found in vertebrate hair cells. Our data suggest that efferent modulation of hair cell function occurs, at least in part, through heteromeric nAChRs assembled from both α9 and α10 subunits.
    Type of Medium: Online Resource
    ISSN: 0027-8424 , 1091-6490
    URL: Article
    DOI: 10.1073/pnas.051622798
    RVK:
    TA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Proceedings of the National Academy of Sciences
    Publication Date: 2001
    detail.hit.zdb_id: 209104-5
    detail.hit.zdb_id: 1461794-8
    SSG: 11
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...