Differential expression of potassium currents in Deiters cells of the guinea pig cochlea

Szűcs, Attila; Somodi, Sándor; Batta, Tamás József; Tóth, Andrea; Szigeti, Gyula P.; Csernoch, László; Panyi, György; Sziklai, István

doi:10.1007/s00424-005-0038-1

Cited by 6 publications

(6 citation statements)

References 29 publications

(47 reference statements)

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“…2). This type of behavior may be related to actions on surface charges at the pore of channels (20) (31,40,41,47). We tested to determine whether these currents were also Cl Ϫ sensitive.…”

Section: K In Ohcs Is Sensitive To 4-ap and Extracellular CLmentioning

confidence: 99%

Extracellular chloride regulation of Kv2.1, contributor to the major outward Kv current in mammalian outer hair cells

Surguchev²,

Bian³

et al. 2012

American Journal of Physiology-Cell Physiology

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Outer hair cells (OHC) function as both receptors and effectors in providing a boost to auditory reception. Amplification is driven by the motor protein prestin, which is under anionic control. Interestingly, we now find that the major, 4-AP-sensitive, outward K+ current of the OHC ( IK) is also sensitive to Cl−, although, in contrast to prestin, extracellularly. IK is inhibited by reducing extracellular Cl− levels, with a linear dependence of 0.4%/mM. Other voltage-dependent K+ (Kv) channel conductances in supporting cells, such as Hensen and Deiters' cells, are not affected by reduced extracellular Cl−. To elucidate the molecular basis of this Cl−-sensitive IK, we looked at potential molecular candidates based on Cl− sensitivity and/or similarities in kinetics. For IK, we identified three different Ca2+-independent components of IK based on the time constant of inactivation: a fast, transient outward current, a rapidly activating, slowly inactivating current ( Ik1), and a slowly inactivating current ( Ik2). Extracellular Cl− differentially affects these components. Because the inactivation time constants of Ik1 and Ik2 are similar to those of Kv1.5 and Kv2.1, we transiently transfected these constructs into CHO cells and found that low extracellular Cl− inhibited both channels with linear current reductions of 0.38%/mM and 0.49%/mM, respectively. We also tested heterologously expressed Slick and Slack conductances, two intracellularly Cl−-sensitive K+ channels, but found no extracellular Cl− sensitivity. The Cl− sensitivity of Kv2.1 and its robust expression within OHCs verified by single-cell RT-PCR indicate that these channels underlie the OHC's extracellular Cl− sensitivity.

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“…2). This type of behavior may be related to actions on surface charges at the pore of channels (20) (31,40,41,47). We tested to determine whether these currents were also Cl Ϫ sensitive.…”

Section: K In Ohcs Is Sensitive To 4-ap and Extracellular CLmentioning

confidence: 99%

Extracellular chloride regulation of Kv2.1, contributor to the major outward Kv current in mammalian outer hair cells

Surguchev²,

Bian³

et al. 2012

American Journal of Physiology-Cell Physiology

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“…Szucs et al [11] reported that two distinct K + channels were identified in Deiters' cells. They suggested the corpulent Deiters' cells mainly had slow inactivating K + current and the lanky Deiters' cells had fast inactivating K + current in addition.…”

Section: Discussionmentioning

confidence: 99%

“…The presence of the different types of outward rectifying K + currents from our results suggests that the modulating procedure may be precise and complex in Deiters' cells. The role of outward rectifying current in Deiters' cells is suggested as repolarizing the membrane potential after depolarization driven by stimulations, such as neurotransmitters [10,11]. Outward K + current can be involved in K + buffering and transportation [23,24] in organ of Corti.…”

Section: Discussionmentioning

confidence: 99%

“…Outward K + current can be involved in K + buffering and transportation [23,24] in organ of Corti. By the K + -Cl - co-transporter, Kcc4 [25], K + released from outer hair cells could be restored in through Deiters cells [11]. Supporting cells of organ of Corti possess gap junctions and one important role of this epithelial gap junction system is the tunnel of the recirculation of potassium ion.…”

Section: Discussionmentioning

confidence: 99%

“…According to these findings, they suggested that more than one type of K + selective channels may exist in Deiters' cells. Using Charybdotoxin and TEA, Szucs et al [11] isolated two distinct potassium channels that are different from Kv1.5 type K + channel in Dieters' cells. Deiters' cells are immersed in the perilymph except the part of phalangeal process, which is facing the endolymph.…”

Section: Introductionmentioning

confidence: 99%

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Potassium Currents in Isolated Deiters' Cells of Guinea Pig

Chung

Nam

Kim

et al. 2013

Korean J Physiol Pharmacol

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Deiters' cells are the supporting cells in organ of Corti and are suggested to play an important role in biochemical and mechanical modulation of outer hair cells. We successfully isolated functionally different K+ currents from Deiters' cells of guinea pig using whole cell patch clamp technique. With high K+ pipette solution, depolarizing step pulses activated strongly outward rectifying currents which were dose-dependently blocked by clofilium, a class III anti-arrhythmic K+ channel blocker. The remaining outward current was transient in time course whereas the clofilium-sensitive outward current showed slow inactivation and delayed rectification. Addition of 5 mM tetraethylammonium (TEA) further blocked the remaining current leaving a very fast inactivating transient outward current. Therefore, at least three different types of K+ current were identified in Deiters' cells, such as fast activating and fast inactivating current, fast activating slow inactivating current, and very fast inactivating transient outward current. Physiological role of them needs to be established.

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Identification and quantification of full‐length BK channel variants in the developing mouse cochlea

Sakai

Harvey

Sokolowski

2011

J of Neuroscience Research

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Maxi K+ (BK) channel diversity is attributed to alternative splicing in the kcnma1 gene. The resultant variants manifest themselves in different cell types, tissues and functions such as excitation, metabolism, and signaling. Immuno-electron microscopy revealed immunogold particle labeling of BK in apical and basal regions of inner and outer hair cells, respectively. Additional labeling occurs in Deiters’ cells and the inner mitochondrial membrane. Identification of full-length sequences reveals 27 BK variants from embryonic and postnatal mouse inner ear, per classification by tail motif, VYR, DEC, and ERL, and by exon usage. Three predicted start codons are found encoding MAN, MSS, and MDA, of which MDA shows the greatest expression through all stages in development, whereas MAN is undetectable. Complex splice sites occur between exons 9 and 10, and 21 and 23. Spliced-in/out exons between 8 and 10 reveal a short fragment composed of exons 8+10, detectable on postnatal-day (PD) 14 and PD30, and a longer fragment composed of exons 8+9+10 that upregulates on embryonic-day (ED) 14. Spliced-in exons 22 or 23 are expressed on ED14 but decrease over time; however, exon 22 increases again on PD34. Using tail specific primers, qRT-PCR from ED14, PD4, 14, and 30, show that BK-VYR and -ERL dominate expression on ED14, whereas DEC dominates after birth in all cochlear regions. The localization of BK and the changes in expression of its exons and tail types, by alternative splicing during development, may contribute to cochlear organization, acquisition of hearing, and intracellular signaling.

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Differential expression of potassium currents in Deiters cells of the guinea pig cochlea

Cited by 6 publications

References 29 publications

Extracellular chloride regulation of Kv2.1, contributor to the major outward Kv current in mammalian outer hair cells

Extracellular chloride regulation of Kv2.1, contributor to the major outward Kv current in mammalian outer hair cells

Potassium Currents in Isolated Deiters' Cells of Guinea Pig

Identification and quantification of full‐length BK channel variants in the developing mouse cochlea

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