Age-related changes in the C57BL/6J mouse cochlea. II. Ultrastructural findings

Shnerson, Allan; Devigne, Colette; Pujol, Rémy

doi:10.1016/0165-3806(81)90060-2

Cited by 145 publications

(87 citation statements)

References 26 publications

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“…Morphologically, IHCs of TH-deficient organs of Corti continued to have large numbers of ribbons and immature synaptic contacts (e.g., showing several ribbons) at least up to P15, when normal maturation and pruning have resulted in fewer and confined single ribbon synapses (Pujol et al, 1980;Shnerson et al, 1981;Sobkowicz et al, 1982;Pujol et al, 1997; this study). The IHCs of 2-week-old Pax8 Ϫ/Ϫ mice were also functionally comparable with immature wt IHCs (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Synapse number (Sobkowicz et al, 1982) and Ca 2ϩ current density Brandt et al, 2003;Johnson et al, 2005) reach a peak at the end of the first postnatal week, when action potentials in IHCs drive presensory transmitter release Glowatzki and Fuchs, 2002;Johnson et al, 2005). Morphologically, this stage is characterized by large active zones anchoring multiple ribbons and branched afferent fibers, giving rise to multiple postsynaptic terminals (Shnerson et al, 1981;Sobkowicz et al, 1982). The number of synapses declines and active zones assume a more confined appearance anchoring a single ribbon at approximately the onset of hearing (Shnerson et al, 1981;Sobkowicz et al, 1982;Pujol et al, 1997;Nemzou et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…Morphologically, this stage is characterized by large active zones anchoring multiple ribbons and branched afferent fibers, giving rise to multiple postsynaptic terminals (Shnerson et al, 1981;Sobkowicz et al, 1982). The number of synapses declines and active zones assume a more confined appearance anchoring a single ribbon at approximately the onset of hearing (Shnerson et al, 1981;Sobkowicz et al, 1982;Pujol et al, 1997;Nemzou et al, 2006). This structural maturation goes along with a decline of the presynaptic Ca 2ϩ current and an improvement of stimulus secretion coupling Johnson et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Maturation of Ribbon Synapses in Hair Cells Is Driven by Thyroid Hormone

Sendin¹,

Bulankina²,

Riedel

et al. 2007

J. Neurosci.

107

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Ribbon synapses of inner hair cells (IHCsϪ/Ϫ mice maintained the normally temporary efferent innervation. Moreover, they lacked large-conductance Ca 2ϩ -activated K ϩ channels and KCNQ4 channels. This together with the persistently increased Ca 2ϩ influx permitted continued action potential generation. We conclude that TH regulates IHC differentiation and is essential for morphological and functional maturation of their ribbon synapses. We suggest that presynaptic dysfunction of IHCs is a mechanism in congenital hypothyroid deafness.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Maturation of Ribbon Synapses in Hair Cells Is Driven by Thyroid Hormone

Sendin¹,

Bulankina²,

Riedel

et al. 2007

J. Neurosci.

107

View full text Add to dashboard Cite

show abstract

“…Its effects variously include fused and disorganized stereocilia, degenerating outer and inner hair cells and supporting cells including the spiral ligament, an atrophic stria vascularis, and loss in myelination and numbers of spiral ganglion cells (Mikaelian et al 1974;Henry and Chole 1980;Shnerson et al 1981;Willott et al 1987;Li and Hultcrantz 1994;Hequembourg and Liberman 2001). These structural changes are more evident at the base compared with the cochlear apex.…”

Section: Introductionmentioning

confidence: 99%

“…These structural changes are more evident at the base compared with the cochlear apex. The resulting age-related decrement in auditory sensitivity has been demonstrated in increased absolute thresholds for auditory-evoked potentials and behavioral-psychophysical tasks (Mikaelian et al 1974;Henry and Chole 1980;Shnerson and Pujol 1981;Willott 1986;Li and Borg 1991;Erway et al 1993; Kazee et al 1995;Spongr et al 1997;Hequembourg and Liberman 2001). Although the specific details of the pattern of sensory loss across frequency vary across studies, the most common outcome is that the early loss is most serious for high tonal frequencies but then spreads across the spectrum of hearing with increasing age.…”

Section: Introductionmentioning

confidence: 99%

Low-Frequency Tone Pips Elicit Exaggerated Startle Reflexes in C57BL/6J Mice with Hearing Loss

Ison

Allen

2003

JARO - Journal of the Association for Research in Otolaryngolog

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The strength of the acoustic startle reflex (ASR) as a function of age was studied in adult C57BL/6J and CBA/CaJ mice, because altered ASR levels are a potential behavioral consequence of the neural reorganization that accompanies the early-onset hearing loss of the C57BL, in contrast to the normal-hearing CBA. For C57BL mice at 14-36 weeks of age, compared with 7-week-old mice, high-frequency thresholds measured with the auditory brainstem response (ABR) were less sensitive by about 25-30 dB while the hearing loss at low frequencies was 10-15 dB, but by 60 weeks losses of 45-50 dB were present across the entire spectrum. Their ASR amplitudes for 16 kHz tone pips were highest at 7 weeks and then declined with age, but, for 4 kHz tones the ASR increased in strength at 18 weeks and beyond to levels above that of the younger mice. This hyperreactivity persisted even in 60-week-old mice. The ASR for 16 kHz stimuli was positively correlated with hearing sensitivity, but the ASR for 4 kHz stimuli was positively correlated with hearing loss for mice that were 18-36 weeks of age. Furthermore, ASR amplitudes for 4 kHz stimuli were positively correlated with the 16 kHz ASR in young C57BL mice but negatively correlated in older mice. There were no similar ASR or ABR changes in adult CBA mice through 19 weeks of age. Correlations between ASR and ABR scores were always weakly positive, and correlations between 4 kHz and 16 kHz ASR amplitudes were always strongly positive. The ASR data in older C57BL mice with hearing loss are consistent with reports describing their increased neural representation of low-frequency sounds and reinforce the value of this strain for studying the functional consequences that accompany age-related cochlear degeneration.

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Olivocochlear innervation of inner and outer hair cells during postnatal maturation: Evidence for a waiting period

1996

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Reconstructions of the efferent innervation of the hamster (Mesocricetus auratus) cochlea were done during postnatal development. Efferent neurons were labeled via injections of biocytin and horseradish peroxidase into the crossed olivocochlear (OC) bundles using an in vitro brainstem technique. Such injections retrogradely labeled cell bodies in ventral periolivary regions of the superior olive consistent with their being medial OC neurons. Anterogradely labeled axons were traced to the cochlea, where they terminated on or below inner hair cells (IHCs) prior to postnatal day 5 (P5). After P5, labeled axons terminated on IHCs and outer hair cells (OHCs) and after P10, the majority of labeled axons terminated on the OHCs. In the electron microscope, small labeled terminals containing densely packed synaptic vesicles were found both adjacent to IHCs (axosomatic) as well as apposed to afferent and efferent fibers below IHCs prior to P5. By P10, large labeled terminals were axosomatic to OHCs and no longer found on IHCs. Consistent with previous reports, these data suggest that medial OC axons form part of an early primary innervation on and below IHCs before terminating on OHCs. This raises the possibility that OC neurons demonstrate a period of waiting below an intermediate target similar to that described in the development of thalamocortical projections.

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Age-related changes in the C57BL/6J mouse cochlea. II. Ultrastructural findings

Cited by 145 publications

References 26 publications

Maturation of Ribbon Synapses in Hair Cells Is Driven by Thyroid Hormone

Maturation of Ribbon Synapses in Hair Cells Is Driven by Thyroid Hormone

Low-Frequency Tone Pips Elicit Exaggerated Startle Reflexes in C57BL/6J Mice with Hearing Loss

Olivocochlear innervation of inner and outer hair cells during postnatal maturation: Evidence for a waiting period

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