K+ Secretion in Strial Marginal Cells is Stimulated via β1-Adrenergic Receptors but not via β2-Adrenergic or Vasopressin Receptors

Wangemann, Philine; Liu, J.; Shimozono, Masami; Schimanski, Sven; Scofield, Margaret A.

doi:10.1007/s00232001067

Cited by 18 publications

(9 citation statements)

References 36 publications

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“…Evidence is emerging that supports the concept that noradrenaline accelerates K + cycling in the cochlea and the vestibular labyrinth. Noradrenaline stimulates the rate of K + secretion in strial marginal cells (Sunose et al 1997; Wangemann et al 2000). Further, outer hair cells appear to contain β 1 ‐adrenergic receptors and cAMP has been shown to stimulate the basolateral channels including the K + channel Kcnq4 (Jagger & Ashmore, 1999).…”

Section: Regulation Of K+ Cyclingmentioning

confidence: 99%

Supporting sensory transduction: cochlear fluid homeostasis and the endocochlear potential

Wangemann

2006

The Journal of Physiology

420

415

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The exquisite sensitivity of the cochlea, which mediates the transduction of sound waves into nerve impulses, depends on the endocochlear potential and requires a highly specialized environment that enables and sustains sensory function. Disturbance of cochlear homeostasis is the cause of many forms of hearing loss including the most frequently occurring syndromic and non-syndromic forms of hereditary hearing loss, Pendred syndrome and Cx26-related deafness. The occurrence of these and other monogenetic disorders illustrates that cochlear fluid homeostasis and the generation of the endocochlear potential are poorly secured by functional redundancy. This review summarizes the most prominent aspects of cochlear fluid homeostasis. It covers cochlear fluid composition, the generation of the endocochlear potential, K + secretion and cycling and its regulation, the role of gap junctions, mechanisms of acid-base homeostasis, and Ca 2+ transport.

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Section: Regulation Of K+ Cyclingmentioning

confidence: 99%

Supporting sensory transduction: cochlear fluid homeostasis and the endocochlear potential

Wangemann

2006

The Journal of Physiology

420

415

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“…These K + transport pathways may be regulated by receptors that couple to G proteins. Several studies have shown the presence of G protein‐coupled receptors in the lateral wall of the cochlea (Wangemann et al. 2000, 2001; Schimanski et al.…”

Section: Introductionmentioning

confidence: 99%

Expression of G protein α subunits in the lateral wall of the rat cochlea

et al. 2003

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Expression of five G protein α subunits was investigated in the rat cochlea by reverse transcription-polymerase chain reaction (RT-PCR) in order to understand their role in the cochlear signal transduction mechanisms. Immunohistochemical techniques were employed to study their distribution in the lateral wall of the cochlea. Total RNA was extracted with guanidine thiocyanate from cochleas and brains of 14-21-day-old rats. The extract was treated with DNase to degrade genomic DNA. After RT, the resulting cDNA was amplified by PCR using primers specific for the nucleotide sequences representing α subunits of heterotrimeric G proteins. The results indicated that mRNA for all five α subunits was expressed in the brain and cochlear samples. For immunohistochemical localization, temporal bones of 6-week-old rats were fixed in 4% paraformaldehyde and 0.1% glutaraldehyde and processed for embedding in paraffin wax. The dewaxed, midmodiolar sections of the cochlea were incubated with subunit-specific polyclonal antibodies. The pattern of immunoreactivity varied for the five G protein α subunits studied in the stria vascularis and spiral ligament. The significance of these findings and the role of G protein α subunits in cochlear fluid homeostasis are discussed.

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“…Several studies have demonstrated the presence of components of G protein‐mediated signal transduction pathways in the lateral wall of the mammalian cochlea. The presence of G protein‐coupled adrenergic (Wangemann et al. 2000; Schimanski et al.…”

Section: Discussionmentioning

confidence: 99%

“…G protein‐coupled receptors may regulate these K + transport pathways in the lateral cochlear wall. Several studies have shown the presence of G protein‐coupled receptors in the lateral wall of the cochlea (Wangemann et al. 2000, 2001; Schimanski et al.…”

Section: Introductionmentioning

confidence: 99%

Immunohistochemical localization of G protein βγ subunits in the lateral wall of the rat cochlea

et al. 2006

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The role of G protein-mediated signal transduction in the production of endolymph, an extracellular fluid of unusual ionic composition, is beginning to be understood. The identity of G α subunits in the stria vascularis and the spiral ligament of the lateral wall of the cochlear duct is well established. However, little is known about the presence of βγ subunits. This study used immunohistochemistry to investigate the distribution of G protein βγ subunits in the lateral wall of the cochlea. Temporal bones of 6-to 8-week-old rats were fixed in 4% paraformaldehyde and 0.1% glutaraldehyde and processed for embedding in paraffin wax. The dewaxed, midmodiolar sections of the cochlea were incubated with subunit-specific polyclonal antibodies. The results show that the pattern of immunoreactivity varies for the G protein β 1-4 and γ 1-3, 5 and 7 subunits in the stria vascularis and spiral ligament. In the stria vascularis, immunoreactivity was detected for β 2, β 3, β 4, γ 1, γ 2 and γ 7 subunits. All five types of fibrocytes in the spiral ligament exhibited positive staining for γ 2 and γ 7. However, immunoreactivity for β 1-4 subunits was variable.Immunoreactivity for γ 3 and γ 5 subunits was not detected in the lateral cochlear wall. The expression pattern of G protein βγ subunits in lateral wall provides a basis for interpreting the functions of G protein-coupled receptors in cochlear fluid homeostasis.

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K+ Secretion in Strial Marginal Cells is Stimulated via β1-Adrenergic Receptors but not via β2-Adrenergic or Vasopressin Receptors

Cited by 18 publications

References 36 publications

Supporting sensory transduction: cochlear fluid homeostasis and the endocochlear potential

Supporting sensory transduction: cochlear fluid homeostasis and the endocochlear potential

Expression of G protein α subunits in the lateral wall of the rat cochlea

Immunohistochemical localization of G protein βγ subunits in the lateral wall of the rat cochlea

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