Extracellular Ca2+ and Mg2+ modulate aminoglycoside blockade of mechanotransducer channel-mediated Ca2+ entry in zebrafish hair cells: an in vivo study with the SIET
- Authors
- Lin, L.Y., Pang, W., Chuang, W.M., Hung, G.Y., Lin, Y.H., and Horng, J.L.
- ID
- ZDB-PUB-130906-2
- Date
- 2013
- Source
- American journal of physiology. Cell physiology 305(10): C1060-8 (Journal)
- Registered Authors
- Horng, Jiun-Lin
- Keywords
- none
- MeSH Terms
-
- Aminoglycosides/pharmacology
- Animals
- Calcium/metabolism
- Calcium/pharmacology*
- Embryo, Nonmammalian/drug effects
- Embryo, Nonmammalian/metabolism
- Female
- Gentamicins/pharmacology*
- Hair Cells, Auditory/drug effects*
- Hair Cells, Auditory/metabolism
- Ion-Selective Electrodes
- Magnesium/metabolism
- Magnesium/pharmacology*
- Male
- Mechanotransduction, Cellular/physiology
- Neomycin/pharmacology*
- Zebrafish
- PubMed
- 24005042 Full text @ Am. J. Physiol. Cell Physiol.
Zebrafish lateral-line hair cells are an in vivo model for studying hair cell development, function, and ototoxicity. However, molecular identification and properties of the mechanotransducer (MET) channel in hair cells are still controversial. In this study, a noninvasive electrophysiological technique, the scanning ion-electrode technique (SIET), was applied for the first time to investigate properties of MET channels in intact zebrafish embryos. Using a Ca2+-selective microelectrode to deflect hair bundles and simultaneously record the Ca2+ flux, the inward Ca2+ flux was detected at stereocilia of hair cells in 2~4-days post-fertilization embryos. The Ca2+ influx was blocked by MET channel blockers (BAPTA, La3+, Gd3+ and curare). In addition, 10 μM aminoglycoside antibiotics (neomycin and gentamicin) were found to effectively block the Ca2+ influx within 10 min. Elevating the external Ca2+ level (0.2 to 2 mM) neutralized the effects of neomycin and gentamicin. However, elevating the Mg2+ level up to 5 mM neutralized the blockade of gentamicin but not neomycin. This study demonstrated MET channel-mediated Ca2+ entry at hair cells and showed the SIET to be a sensitive approach for functionally assaying the MET channel in zebrafish.