Patch clamp recordings of hair cells isolated from zebrafish auditory and vestibular end organs

The senses of hearing and balance in vertebrates are transduced by hair cells in the inner ear. Hair cells from a wide variety of organisms have been described electrophysiologically but this is the first report of the application of these techniques to the genetically tractable zebrafish model system. Auditory and vestibular hair cells isolated from zebrafish lagenae and utricles were patch clamped and both inward and outward currents under voltage clamp, and changes in membrane potential under current clamp were recorded. Cells displayed substantial diversity in their morphology, constellation of channel types, and level of excitability. While all cells showed evidence of the presence of fast-inactivating (A-type) K+ channels, other K+ channel types, including delayed rectifier, inward rectifier and large conductance Ca2+-activated K+ (BK) channels were less common. Recorded Ca2+ currents were identified pharmacologically as L-type. Non-linear regenerative voltage responses were evoked in more than half of the cells studied.