Abstract
‘Slow’ motility (shape changes over seconds to minutes) of the mammalian cochlear outer hair cell (OHC) could play a protection role from intense sound pressure and is associated with elevation of the cytosolic free Ca 2+ concentration ([Ca 2+] i). In the present work, a new approach was elaborated using fluorescent imaging for continuous monitoring of both [Ca 2+] i changes and slow motility of OHCs employing the Ca 2+ fluorescent indicator Fura-2. Whole OHC fluorescence and that of cell segments were analyzed to discriminate between fluorescence changes caused by [Ca 2+] i rise and those related to change of the cell shape. The reliability of the method was examined by simultaneous monitoring of [Ca 2+] i and OHC length changes induced by change of buffer osmolarity or by increase of KCl concentration. The method revealed that the time course of [Ca 2+] i increase and rate of cell shortening often do not coincide. It was also observed that [Ca 2+] i increased in 70 mM KCl more slowly than the rate of KCl delivery to OHCs. The comparison of the time courses of [Ca 2+] i elevation, induced by increase of K +/Na + ratio and by substitution of Na + with N-methyl- D-glucamine +, indicated that the relatively slow kinetics of [Ca 2+] i increase in the OHC is partially attributed to regulation of Ca 2+ homeostasis by the Na +/Ca 2+ exchanger.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
