The normal sensing of sounds and motion by the inner ear is critically dependent upon the ionic composition of endolymph, the fluid bathing the apical side of the hair cells. Epithelial cells responsible for production and maintenance of endolymph have previously been studied almost exclusively by observations of transepithelial events (e.g., ion fluxes, transepithelial voltage and resistance), and by measurements of membrane potential and cell volume. These measurements have pointed to the existence of many intracellular regulatory mechanisms which are fundamental to the normal function of these cells and the normal function of hearing and balance. Data on two cell types in particular, dark cells and transitional cells, suggest their involvement in the homeostasis of mono- and di-valent cations in endolymph. The studies proposed in this application are aimed at understanding the mechanisms involved in the regulation of ion transport in the inner ear. The primary technique to be utilized is quantitative microfluorimetry, a technique which allows the measurement of intracellular constituents with fluorescent probes.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29DC001098-02
Application #
3461818
Study Section
Hearing Research Study Section (HAR)
Project Start
1992-01-01
Project End
1996-12-31
Budget Start
1993-01-01
Budget End
1993-12-31
Support Year
2
Fiscal Year
1993
Total Cost
Indirect Cost
Name
Father Flanagan's Boys' Home
Department
Type
DUNS #
City
Boys Town
State
NE
Country
United States
Zip Code
68010
Wangemann, P (1997) [Potassium ion secretion and generation of the endocochlear potential in the stria vascularis] HNO 45:205-9
Wangemann, P; Liu, J; Shiga, N (1996) Vestibular dark cells contain the Na+/H+ exchanger NHE-1 in the basolateral membrane. Hear Res 94:94-106
Wangemann, P; Shen, Z; Liu, J (1996) K(+)-induced stimulation of K+ secretion involves activation of the IsK channel in vestibular dark cells. Hear Res 100:201-10
Wangemann, P; Liu, J (1996) Osmotic water permeability of capillaries from the isolated spiral ligament: new in-vitro techniques for the study of vascular permeability and diameter. Hear Res 95:49-56
Wangemann, P; Liu, J; Shiga, N (1995) The pH-sensitivity of transepithelial K+ transport in vestibular dark cells. J Membr Biol 147:255-62
Wangemann, P; Liu, J; Shen, Z et al. (1995) Hypo-osmotic challenge stimulates transepithelial K+ secretion and activates apical IsK channel in vestibular dark cells. J Membr Biol 147:263-73
Shen, Z; Liu, J; Marcus, D C et al. (1995) DIDS increases K+ secretion through an IsK channel in apical membrane of vestibular dark cell epithelium of gerbil. J Membr Biol 146:283-91
Shiga, N; Wangemann, P (1995) Ion selectivity of volume regulatory mechanisms present during a hypoosmotic challenge in vestibular dark cells. Biochim Biophys Acta 1240:48-54
Marcus, D C; Liu, J; Wangemann, P (1994) Transepithelial voltage and resistance of vestibular dark cell epithelium from the gerbil ampulla. Hear Res 73:101-8
Takeuchi, S; Wangemann, P (1993) Aminoglycoside antibiotics inhibit maxi-K+ channel in single isolated cochlear efferent nerve terminals. Hear Res 67:13-9

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