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. 1994 Feb 1;91(3):1153–1157. doi: 10.1073/pnas.91.3.1153

Intra- and extracellular calcium modulates stereocilia stiffness on chick cochlear hair cells.

S S Pae 1, J C Saunders 1
PMCID: PMC521472  PMID: 8302845

Abstract

Segments of the chick basilar papilla were isolated and maintained in culture medium. The sensory hair bundle of individual hair cells was observed with light microscopy and stimulated with a water microjet at 600 Hz. Hair bundle motion was slowed by illuminating the microscope with stroboscopic light, and water jet intensity was systematically varied in decibel (dB) steps until a visual detection level (VDL) threshold of hair bundle motion was achieved. The VDL threshold of many hair cells was measured in each isolated papilla. However, only one of eight extracellular calcium concentrations (0.0, 0.0001, 0.001, 0.01, 0.1, 1.25, 6.0, and 12.0 mM) was used with each papilla. In a second series, a calcium ionophore (ionomycin) was added to the culture medium, and VDL thresholds were again measured at seven of these extracellular calcium concentrations. With extracellular calcium alone, the stimulus level needed to achieve threshold was reduced by 2.73 dB between 0.1 and 0.01 mM. This change in threshold represented a 1.37-fold decrease in hair bundle stiffness. When ionomycin was added to the culture medium, a progressively greater stimulus intensity was needed to achieve threshold as calcium concentration increased. The 11.7-dB increase in threshold, with the addition of ionomycin, between 0.0001 and 6.0 mM extracellular calcium was equivalent to a 3.85-fold increase in bundle stiffness. These large changes in hair-bundle stiffness, as a function of the extra- or intracellular calcium environment, may play an important role in the micromechanical behavior of the hair cell during sound simulation.

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Selected References

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  1. Bosher S. K., Warren R. L. Very low calcium content of cochlear endolymph, an extracellular fluid. Nature. 1978 Jun 1;273(5661):377–378. doi: 10.1038/273377a0. [DOI] [PubMed] [Google Scholar]
  2. Brundin L., Flock A., Canlon B. Tuned motile responses of isolated cochlear outer hair cells. Acta Otolaryngol Suppl. 1989;467:229–234. doi: 10.3109/00016488909138342. [DOI] [PubMed] [Google Scholar]
  3. Crawford A. C., Evans M. G., Fettiplace R. The actions of calcium on the mechano-electrical transducer current of turtle hair cells. J Physiol. 1991 Mar;434:369–398. doi: 10.1113/jphysiol.1991.sp018475. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Crawford A. C., Fettiplace R. An electrical tuning mechanism in turtle cochlear hair cells. J Physiol. 1981 Mar;312:377–412. doi: 10.1113/jphysiol.1981.sp013634. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Csukas S. R., Rosenquist T. H., Mulroy M. J. Connections between stereocilia in auditory hair cells of the alligator lizard. Hear Res. 1987;30(2-3):147–155. doi: 10.1016/0378-5955(87)90132-8. [DOI] [PubMed] [Google Scholar]
  6. Dulon D., Zajic G., Schacht J. Differential motile response of isolated inner and outer hair cells to stimulation by potassium and calcium ions. Hear Res. 1991 Mar;52(1):225–231. doi: 10.1016/0378-5955(91)90202-k. [DOI] [PubMed] [Google Scholar]
  7. Dulon D., Zajic G., Schacht J. Increasing intracellular free calcium induces circumferential contractions in isolated cochlear outer hair cells. J Neurosci. 1990 Apr;10(4):1388–1397. doi: 10.1523/JNEUROSCI.10-04-01388.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Eatock R. A., Corey D. P., Hudspeth A. J. Adaptation of mechanoelectrical transduction in hair cells of the bullfrog's sacculus. J Neurosci. 1987 Sep;7(9):2821–2836. doi: 10.1523/JNEUROSCI.07-09-02821.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Ferrary E., Tran Ba Huy P., Roinel N., Bernard C., Amiel C. Calcium and the inner ear fluids. Acta Otolaryngol Suppl. 1988;460:13–17. doi: 10.3109/00016488809125130. [DOI] [PubMed] [Google Scholar]
  10. Flock A., Bretscher A., Weber K. Immunohistochemical localization of several cytoskeletal proteins in inner ear sensory and supporting cells. Hear Res. 1982 May;7(1):75–89. doi: 10.1016/0378-5955(82)90082-x. [DOI] [PubMed] [Google Scholar]
  11. Grillner S., Matsushima T. The neural network underlying locomotion in lamprey--synaptic and cellular mechanisms. Neuron. 1991 Jul;7(1):1–15. doi: 10.1016/0896-6273(91)90069-c. [DOI] [PubMed] [Google Scholar]
  12. Guttenplan M., Jenkins O. H., Saunders J. C. Structural changes in hair cells after incubation in tissue culture medium. Hear Res. 1989 Dec;43(1):47–53. doi: 10.1016/0378-5955(89)90058-0. [DOI] [PubMed] [Google Scholar]
  13. Hacohen N., Assad J. A., Smith W. J., Corey D. P. Regulation of tension on hair-cell transduction channels: displacement and calcium dependence. J Neurosci. 1989 Nov;9(11):3988–3997. doi: 10.1523/JNEUROSCI.09-11-03988.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Howard J., Ashmore J. F. Stiffness of sensory hair bundles in the sacculus of the frog. Hear Res. 1986;23(1):93–104. doi: 10.1016/0378-5955(86)90178-4. [DOI] [PubMed] [Google Scholar]
  15. Howard J., Roberts W. M., Hudspeth A. J. Mechanoelectrical transduction by hair cells. Annu Rev Biophys Biophys Chem. 1988;17:99–124. doi: 10.1146/annurev.bb.17.060188.000531. [DOI] [PubMed] [Google Scholar]
  16. Hudspeth A. J., Corey D. P. Sensitivity, polarity, and conductance change in the response of vertebrate hair cells to controlled mechanical stimuli. Proc Natl Acad Sci U S A. 1977 Jun;74(6):2407–2411. doi: 10.1073/pnas.74.6.2407. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Kimitsuki T., Ohmori H. The effect of caged calcium release on the adaptation of the transduction current in chick hair cells. J Physiol. 1992 Dec;458:27–40. doi: 10.1113/jphysiol.1992.sp019404. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Kössl M., Richardson G. P., Russell I. J. Stereocilia bundle stiffness: effects of neomycin sulphate, A23187 and concanavalin A. Hear Res. 1990 Mar;44(2-3):217–229. doi: 10.1016/0378-5955(90)90082-z. [DOI] [PubMed] [Google Scholar]
  19. Liu C., Hermann T. E. Characterization of ionomycin as a calcium ionophore. J Biol Chem. 1978 Sep 10;253(17):5892–5894. [PubMed] [Google Scholar]
  20. Ohmori H. Mechanical stimulation and Fura-2 fluorescence in the hair bundle of dissociated hair cells of the chick. J Physiol. 1988 May;399:115–137. doi: 10.1113/jphysiol.1988.sp017071. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Ohmori H. Mechano-electrical transduction currents in isolated vestibular hair cells of the chick. J Physiol. 1985 Feb;359:189–217. doi: 10.1113/jphysiol.1985.sp015581. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Orman S., Flock A. Active control of sensory hair mechanics implied by susceptibility to media that induce contraction in muscle. Hear Res. 1983 Sep;11(3):261–266. doi: 10.1016/0378-5955(83)90061-8. [DOI] [PubMed] [Google Scholar]
  23. Saunders J. C., Szymko Y. M. The design, calibration, and use of a water microjet for stimulating hair cell sensory hair bundles. J Acoust Soc Am. 1989 Nov;86(5):1797–1804. doi: 10.1121/1.398612. [DOI] [PubMed] [Google Scholar]
  24. Smith J. B., Zheng T., Lyu R. M. Ionomycin releases calcium from the sarcoplasmic reticulum and activates Na+/Ca2+ exchange in vascular smooth muscle cells. Cell Calcium. 1989 Apr;10(3):125–134. doi: 10.1016/0143-4160(89)90066-3. [DOI] [PubMed] [Google Scholar]
  25. Szymko Y. M., Dimitri P. S., Saunders J. C. Stiffness of hair bundles in the chick cochlea. Hear Res. 1992 May;59(2):241–249. doi: 10.1016/0378-5955(92)90120-c. [DOI] [PubMed] [Google Scholar]
  26. Tilney L. G., Saunders J. C. Actin filaments, stereocilia, and hair cells of the bird cochlea. I. Length, number, width, and distribution of stereocilia of each hair cell are related to the position of the hair cell on the cochlea. J Cell Biol. 1983 Mar;96(3):807–821. doi: 10.1083/jcb.96.3.807. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Tilney M. S., Tilney L. G., Stephens R. E., Merte C., Drenckhahn D., Cotanche D. A., Bretscher A. Preliminary biochemical characterization of the stereocilia and cuticular plate of hair cells of the chick cochlea. J Cell Biol. 1989 Oct;109(4 Pt 1):1711–1723. doi: 10.1083/jcb.109.4.1711. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Yamashita T., Amano H., Harada N., Su Z. L., Kumazawa T., Tsunoda Y., Tashiro Y. Calcium distribution and mobilization during depolarization in single cochlear hair cells. Imaging microscopy and fura-2. Acta Otolaryngol. 1990 Mar-Apr;109(3-4):256–262. doi: 10.3109/00016489009107441. [DOI] [PubMed] [Google Scholar]

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