Biophysical Journal 73: 1243-1252 (1997)
© 1997 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hall, J D Articles by Jaramillo, F Search for Related Content PubMed PubMed Citation Articles by Hall, J D Articles by Jaramillo, F

Endogenous buffers limit the spread of free calcium in hair cells.

Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.

ABSTRACT

Mobile Ca2+ buffers in hair cells have been postulated to play a dual role. On one hand, they carry incoming Ca2+ away from synaptic areas, allowing synapses to be rapidly reset. On the other hand, they limit the spread of free Ca2+ into the cell, preventing cross-talk between different pathways that employ Ca2+ as a second messenger. We have obtained evidence for such mobile Ca2+ buffers in hair cells by comparing the patterns of Ca2+-induced fluo-3 fluorescence under whole-cell and perforated-patch recording conditions. Fluorescent signals under perforated-patch conditions are relatively weak and are limited to the immediate vicinity of the membrane. These observations can be explained by a diffusion-reaction scheme that, in addition to Ca2+ and fluo-3, incorporates endogenous fixed and mobile Ca2+ buffers. Our experiments also suggest that the mobility of the endogenous buffer might be higher than previously thought. A high buffer mobility is expected to enhance the cell's ability to rapidly modulate transmitter release.

This article has been cited by other articles:

				C. M. Hackney, S. Mahendrasingam, E. M. C. Jones, and R. Fettiplace The Distribution of Calcium Buffering Proteins in the Turtle Cochlea J. Neurosci., June 1, 2003; 23(11): 4577 - 4589. [Abstract] [Full Text] [PDF]

				A. Rodriguez-Contreras and E. N. Yamoah Effects of Permeant Ion Concentrations on the Gating of L-Type Ca2+ Channels in Hair Cells Biophys. J., May 1, 2003; 84(5): 3457 - 3469. [Abstract] [Full Text] [PDF]

				J. Oberwinkler and D. G. Stavenga Calcium imaging demonstrates colocalization of calcium influx and extrusion in fly photoreceptors PNAS, July 18, 2000; 97(15): 8578 - 8583. [Abstract] [Full Text] [PDF]

				D. A. DiGregorio, A. Peskoff, and J. L. Vergara Measurement of Action Potential-Induced Presynaptic Calcium Domains at a Cultured Neuromuscular Junction J. Neurosci., September 15, 1999; 19(18): 7846 - 7859. [Abstract] [Full Text] [PDF]

				F. Mammano, G. I. Frolenkov, L. Lagostena, I. A. Belyantseva, M. Kurc, V. Dodane, A. Colavita, and B. Kachar ATP-Induced Ca2+ Release in Cochlear Outer Hair Cells: Localization of an Inositol Triphosphate-Gated Ca2+ Store to the Base of the Sensory Hair Bundle J. Neurosci., August 15, 1999; 19(16): 6918 - 6929. [Abstract] [Full Text] [PDF]

				A. J. Ricci, Y-C. Wu, and R. Fettiplace The Endogenous Calcium Buffer and the Time Course of Transducer Adaptation in Auditory Hair Cells J. Neurosci., October 15, 1998; 18(20): 8261 - 8277. [Abstract] [Full Text] [PDF]

				E. A. Lumpkin and A. J. Hudspeth Regulation of Free Ca2+ Concentration in Hair-Cell Stereocilia J. Neurosci., August 15, 1998; 18(16): 6300 - 6318. [Abstract] [Full Text] [PDF]

				A. Rodriguez-Contreras, W. Nonner, and E. N. Yamoah Ca2+ transport properties and determinants of anomalous mole fraction effects of single voltage-gated Ca2+ channels in hair cells from bullfrog saccule J. Physiol., February 1, 2002; 538(3): 729 - 745. [Abstract] [Full Text] [PDF]