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. 1997 Sep;73(3):1243–1252. doi: 10.1016/S0006-3495(97)78157-8

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

J D Hall 1, S Betarbet 1, F Jaramillo 1
PMCID: PMC1181024  PMID: 9284292

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.

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Selected References

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