Facilitating efferent inhibition of inner hair cells in the cochlea of the neonatal rat

Research output: Contribution to journalArticle

Abstract

Cholinergic brainstem neurones make inhibitory synapses on outer hair cells (OHCs) in the mature mammalian cochlea and on inner hair cells (IHCs) prior to the onset of hearing. We used electrical stimulation in an excised organ of Corti preparation to examine evoked release of acetylcholine (ACh) onto neonatal IHCs from these efferent fibres. Whole-cell voltage-clamp recording revealed that low frequency (0.25-1 Hz) electrical stimulation produced evoked inhibitory post-synaptic currents (IPSCs) at a relatively high fraction of failures (65%) and with mean amplitudes of about -20 pA at -90 mV, corresponding to a quantum content of ∼1. Evoked IPSCs had biphasic waveforms at -60 mV, were blocked reversibly by α-bungarotoxin and strychnine and are most likely mediated by the α9/0 acetylcholine receptor, with subsequent activation of calcium-dependent potassium (SK2) channels. Paired pulse stimulation with intervals of 10-100 ms caused facilitation of 200-300% in the mean IPSC amplitude. A train of 10 pulses with an interpulse interval of 25 ms produced increasingly larger IPSCs with maximum amplitudes greater than -100 pA due to facilitation and summation throughout the train. Repetitive efferent stimulation at 5 Hz or higher hyperpolarized IHCs by 5-10 mV and could completely prevent the generation of calcium action potentials normally evoked by depolarizing current injection.

Original languageEnglish (US)
Pages (from-to)49-59
Number of pages11
JournalJournal of Physiology
Volume566
Issue number1
DOIs
StatePublished - Jul 1 2005

Fingerprint

Inner Auditory Hair Cells
Cochlea
Outer Auditory Hair Cells
Electric Stimulation
Calcium-Activated Potassium Channels
Organ of Corti
Bungarotoxins
Strychnine
Cholinergic Neurons
Cholinergic Receptors
Synapses
Hearing
Action Potentials
Brain Stem
Acetylcholine
Calcium
Injections
Inhibition (Psychology)

ASJC Scopus subject areas

  • Physiology

Cite this

Facilitating efferent inhibition of inner hair cells in the cochlea of the neonatal rat. / Goutman, Juan Diego; Fuchs, Paul Albert; Glowatzki, Elisabeth B.

In: Journal of Physiology, Vol. 566, No. 1, 01.07.2005, p. 49-59.

Research output: Contribution to journalArticle

@article{fd7260de4ec3468f9d3e4dd7f809c7e5,
title = "Facilitating efferent inhibition of inner hair cells in the cochlea of the neonatal rat",
abstract = "Cholinergic brainstem neurones make inhibitory synapses on outer hair cells (OHCs) in the mature mammalian cochlea and on inner hair cells (IHCs) prior to the onset of hearing. We used electrical stimulation in an excised organ of Corti preparation to examine evoked release of acetylcholine (ACh) onto neonatal IHCs from these efferent fibres. Whole-cell voltage-clamp recording revealed that low frequency (0.25-1 Hz) electrical stimulation produced evoked inhibitory post-synaptic currents (IPSCs) at a relatively high fraction of failures (65{\%}) and with mean amplitudes of about -20 pA at -90 mV, corresponding to a quantum content of ∼1. Evoked IPSCs had biphasic waveforms at -60 mV, were blocked reversibly by α-bungarotoxin and strychnine and are most likely mediated by the α9/0 acetylcholine receptor, with subsequent activation of calcium-dependent potassium (SK2) channels. Paired pulse stimulation with intervals of 10-100 ms caused facilitation of 200-300{\%} in the mean IPSC amplitude. A train of 10 pulses with an interpulse interval of 25 ms produced increasingly larger IPSCs with maximum amplitudes greater than -100 pA due to facilitation and summation throughout the train. Repetitive efferent stimulation at 5 Hz or higher hyperpolarized IHCs by 5-10 mV and could completely prevent the generation of calcium action potentials normally evoked by depolarizing current injection.",
author = "Goutman, {Juan Diego} and Fuchs, {Paul Albert} and Glowatzki, {Elisabeth B}",
year = "2005",
month = "7",
day = "1",
doi = "10.1113/jphysiol.2005.087460",
language = "English (US)",
volume = "566",
pages = "49--59",
journal = "Journal of Physiology",
issn = "0022-3751",
publisher = "Wiley-Blackwell",
number = "1",

}

TY - JOUR

T1 - Facilitating efferent inhibition of inner hair cells in the cochlea of the neonatal rat

AU - Goutman, Juan Diego

AU - Fuchs, Paul Albert

AU - Glowatzki, Elisabeth B

PY - 2005/7/1

Y1 - 2005/7/1

N2 - Cholinergic brainstem neurones make inhibitory synapses on outer hair cells (OHCs) in the mature mammalian cochlea and on inner hair cells (IHCs) prior to the onset of hearing. We used electrical stimulation in an excised organ of Corti preparation to examine evoked release of acetylcholine (ACh) onto neonatal IHCs from these efferent fibres. Whole-cell voltage-clamp recording revealed that low frequency (0.25-1 Hz) electrical stimulation produced evoked inhibitory post-synaptic currents (IPSCs) at a relatively high fraction of failures (65%) and with mean amplitudes of about -20 pA at -90 mV, corresponding to a quantum content of ∼1. Evoked IPSCs had biphasic waveforms at -60 mV, were blocked reversibly by α-bungarotoxin and strychnine and are most likely mediated by the α9/0 acetylcholine receptor, with subsequent activation of calcium-dependent potassium (SK2) channels. Paired pulse stimulation with intervals of 10-100 ms caused facilitation of 200-300% in the mean IPSC amplitude. A train of 10 pulses with an interpulse interval of 25 ms produced increasingly larger IPSCs with maximum amplitudes greater than -100 pA due to facilitation and summation throughout the train. Repetitive efferent stimulation at 5 Hz or higher hyperpolarized IHCs by 5-10 mV and could completely prevent the generation of calcium action potentials normally evoked by depolarizing current injection.

AB - Cholinergic brainstem neurones make inhibitory synapses on outer hair cells (OHCs) in the mature mammalian cochlea and on inner hair cells (IHCs) prior to the onset of hearing. We used electrical stimulation in an excised organ of Corti preparation to examine evoked release of acetylcholine (ACh) onto neonatal IHCs from these efferent fibres. Whole-cell voltage-clamp recording revealed that low frequency (0.25-1 Hz) electrical stimulation produced evoked inhibitory post-synaptic currents (IPSCs) at a relatively high fraction of failures (65%) and with mean amplitudes of about -20 pA at -90 mV, corresponding to a quantum content of ∼1. Evoked IPSCs had biphasic waveforms at -60 mV, were blocked reversibly by α-bungarotoxin and strychnine and are most likely mediated by the α9/0 acetylcholine receptor, with subsequent activation of calcium-dependent potassium (SK2) channels. Paired pulse stimulation with intervals of 10-100 ms caused facilitation of 200-300% in the mean IPSC amplitude. A train of 10 pulses with an interpulse interval of 25 ms produced increasingly larger IPSCs with maximum amplitudes greater than -100 pA due to facilitation and summation throughout the train. Repetitive efferent stimulation at 5 Hz or higher hyperpolarized IHCs by 5-10 mV and could completely prevent the generation of calcium action potentials normally evoked by depolarizing current injection.

UR - http://www.scopus.com/inward/record.url?scp=22144497747&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=22144497747&partnerID=8YFLogxK

U2 - 10.1113/jphysiol.2005.087460

DO - 10.1113/jphysiol.2005.087460

M3 - Article

VL - 566

SP - 49

EP - 59

JO - Journal of Physiology

JF - Journal of Physiology

SN - 0022-3751

IS - 1

ER -