Cochlear nucleus cell size changes in the dalmatian: Model of congenital deafness

Niparko, John K.; Finger, Peter A.

doi:10.1016/s0194-5998(97)70179-7

Cited by 27 publications

(21 citation statements)

References 37 publications

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“…There were also significant decreases in labeled cells in the lateral cortex in both the ventral (32%, p < 0.01) and dorsal (47%, p <0.04) regions. In the lateral cortex the medium sized cells were most affected by deafness, becoming a smaller proportion of those retaining label, However, we cannot rule out that there may be decreases in cell size, as reported to occur with deafening (Kawano et al, 1997;Lesperance et al, 1995;Lustig et al, 1994;Niparko, 1999;Niparko et al, 1997;Sie et al, 1992;Willott et al, 1994). Such a decrease in cell size could bring neurons from a previous classification of medium sized to the class of small neurons.…”

Section: In Situ Hybridizationmentioning

confidence: 79%

“…As such, one modality for TREK-2 activation is through mechanical gating via stretching the cell membrane (Kim et al, 2005). Decreases in cell size (Kawano et al, 1997;Lesperance et al, 1995;Lustig et al, 1994;Niparko, 1999;Niparko et al, 1997;Sie et al, 1992;Willott et al, 1994) or even flattening of synapses (Gulley et al, 1978;Ryugo et al, 2005) that have been reported following deafness could therefore influence TREK-2 activity and expression. It is interesting that the deafness-associated decrease in TREK-2 expression was transient, significant only at 3 days following deafness, while decreases in the other three subunits were more sustained.…”

Section: Discussionmentioning

confidence: 99%

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Deafness associated changes in two-pore domain potassium channels in the rat inferior colliculus

et al. 2007

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Two-pore potassium channels can influence neuronal excitability by regulating background leakage of potassium ions and resting membrane potential. The present study used quantitative real time PCR and in situ hybridization to determine if the decreased activity from deafness would induce changes in two-pore potassium channel subunit expression in the rat inferior colliculus. Ten subunits were assessed with qRT-PCR at 3 days, 3 weeks and 3 months following bilateral cochlear ablation. TASK-1, TASK-5 and THIK-2 showed significant decreases in expression at all three times assessed. TASK-5, relatively specific to auditory neurons, had the greatest decrease. TWIK-1 was significantly decreased at 3 weeks and 3 months following deafness and TREK-2 was only significantly decreased at 3 days. TASK-3, TWIK-2, THIK-1, TRAAK and TREK-1 did not show any significant changes in gene expression. In situ hybridization was used to examine TASK-1, TASK-5, TWIK-1 and THIK-2 in the central nucleus, dorsal cortex and lateral (external) cortex of the IC in normal hearing animals and at 3 weeks following deafening. All four subunits showed expression in neurons throughout IC subdivisions in normal hearing rats, with TASK-5 having the greatest overall number of labeled neurons. There was no co-localization of subunit expression with GFAP immunostaining, indicating no expression in glia. Three weeks following deafening there was a significant decrease in the number of neurons expressing TASK-1 and THIK-2 in the IC, while TASK-5 had significant decreases in the central nucleus and dorsal cortex and TWIK-1 in the lateral and dorsal cortices. Two-pore potassium channels (K 2p ) are a class of open rectifying potassium selective channels (Ketchum et al., 1995) that, when activated, allow a background leakage of potassium ions that raises the resting membrane potential to hyperpolarizing levels, resulting in decreased neuronal excitability (see Lesage and Lazdunski, 2000;Goldstein et al., 2001;Patel and Honore, 2001; Plant et al., 2005 for reviews). There are, to date, 18 subunits in the K 2p channel family that have been divided into different classes based on what is know about their sensitivities. The TASK-1 (K 2p 3.1, KCNK3), TASK-3 (K 2p 9.1, KCNK9) and TWIK-1 (K 2p 1.1, KCNK1) subunits are widely expressed throughout the brain but have been reported to have only moderate expression in the auditory brain stem Talley et al., 2001). The TASK-5 (K 2p 15.1, KCNK15) subunit has a relatively selective expression, primarily found in Author for correspondence: Dr. Richard A. Altschuler, KHRI, Department of Otolaryngology, The University of Michigan, 1301 East Ann Street, Ann Arbor, MI, Tel: (734) Fax: (734) 764-0014, E-mail: E-mail: shuler@umich.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof befo...

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Section: In Situ Hybridizationmentioning

confidence: 79%

Section: Discussionmentioning

confidence: 99%

Deafness associated changes in two-pore domain potassium channels in the rat inferior colliculus

et al. 2007

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“…However, significant degeneration of the spiral ganglion neurons and degenerative changes in the CN still occur. A reduction of 25-50% in total volume of the CN and a decrease of 20-40% in spherical cell body size in the AVCN has been reported in cats deafened by ototoxic drugs as neonates (Hultcrantz et al, 1991;Lustig et al, 1994;Hardie and Shepherd, 1999;Osofsky et al, 2001;Leake et al, 2006) and in congenitally deaf animals (Saada et al, 1996;Niparko and Finger, 1997).…”

Section: Introductionmentioning

confidence: 92%

Effects of age at onset of deafness and electrical stimulation on the developing cochlear nucleus in cats

et al. 2008

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This study examined the effects of deafness and intracochlear electrical stimulation on the anatomy of the cochlear nucleus (CN) after a brief period of normal auditory development early in life. Kittens were deafened by systemic ototoxic drug injections either as neonates or starting at postnatal day 30. Total CN volume, individual CN subdivision volumes, and cross-sectional areas of spherical cell somata in the anteroventral CN (AVCN) were compared in neonatally deafened and 30-day deafened groups at 8 weeks of age and in young adults after approximately 6 months of electrical stimulation initiated at 8 weeks of age. Both neonatal and early acquired hearing loss resulted in a reduction in CN volume as compared to normal hearing cats. Comparison of 8- and 32-week old groups indicated that the CN continued to grow in both deafened groups despite the absence of auditory input. Preserving normal auditory input for 30 days resulted in a significant increase in both total CN volume and cross-sectional areas of spherical cell somata, as compared to neonatally deafened animals. Restoring auditory input in these developing animals by unilateral intracochlear electrical stimulation did not elicit any difference in CN volume between the two sides, but resulted in 7% larger spherical cell size on the stimulated side. Overall, the brief period of normal auditory development and subsequent electrical stimulation maintained CN volume at 80% of normal and spherical cell size at 86% of normal ipsilateral to the implant as compared to 67% and 74%, respectively, in the neonatally deafened group.

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“…There have been numerous reports of deafness-associated decreases in cell size in the cochlear nucleus (Kawano et al, 1997;Lesperance et al, 1995;Lustig et al, 1994;Niparko, 1999;Niparko and Finger, 1997;Sie and Rubel, 1992;Willott et al, 1994). One modality for the activation of TREK is through mechanical gating via stretching the cell membrane .…”

Section: Cell Volume Regulationmentioning

confidence: 99%

Deafness associated changes in expression of two-pore domain potassium channels in the rat cochlear nucleus

et al. 2006

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Two-pore domain potassium channels ( ) play an important role in setting resting membrane potential by regulating background leakage of potassium ions, which in turn controls neuronal excitability. To determine whether these channels contribute to activity-dependent plasticity following deafness, we used quantitative real-time PCR to examine the expression of 10 subunits in the rat cochlear nucleus at 3 days, 3 weeks and 3 months after bilateral cochlear ablation. There was a large sustained decrease in the expression of TASK-5, a subunit that is predominantly expressed in auditory brain stem neurons, and in the TASK-1 subunit which is highly expressed in several types of cochlear nucleus neurons. TWIK-1 and THIK-2 also showed significant decreases in expression that were maintained across all time points. TWIK-2, TREK-1 and TREK-2 showed no significant change in expression at 3 days but showed large decreases at 3 weeks and 3 months following deafness. TRAAK and TASK-3 subunits showed significant decreases at 3 days and 3 weeks following deafness, but these differences were no longer significant at 3 months. Dramatic changes in expression of subunits suggest these channels may play a role in deafness-associated changes in the excitability of cochlear nucleus neurons.

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Cochlear nucleus cell size changes in the dalmatian: Model of congenital deafness

Cited by 27 publications

References 37 publications

Deafness associated changes in two-pore domain potassium channels in the rat inferior colliculus

Deafness associated changes in two-pore domain potassium channels in the rat inferior colliculus

Effects of age at onset of deafness and electrical stimulation on the developing cochlear nucleus in cats

Deafness associated changes in expression of two-pore domain potassium channels in the rat cochlear nucleus

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