Dr Helen Kennedy
Dr Helen Kennedy
University Walk, Bristol
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Signal transduction in the development of hearing
Auditory hair cells are responsible for our ability to hear, and irreversible damage of these delicate sensory cells is the most common cause of deafness in the UK.
My research focuses on the role of intracellular calcium in signal transduction in mammalian hair cells. Increases in intracellular calcium are involved in several important processes in mammalian hair cells and my lab focuses on its role in adaptation of the mechanotransducer current and in triggering of transmitter release.
The hair cell bundle is exquisitely sensitive to mechanical motion, with deflections of less than the diameter of an atom being sufficient to open transducer channels in vivo. We have studied the transducer current and its calcium dependent adaptation during development and after the onset of hearing. We have shown that the mammalian auditory system is capable of extremely fast adaptation in the order of 100 microseconds or less, and that the speed of adaptation is related to the characteristic frequency of the hair cell.
We are also interested in calcium signaling in the basal pole of the inner hair cell, close to afferent transmitter release sites. Using simultaneous patch-clamping and confocal imaging we have demonstrated that calcium induced calcium release occurs in the basal pole of hair cells. We are now studying its role in triggering transmitter release from the inner hair cell synapse during development of hearing.
Signal transduction, deafness, intracellular calcium
- Calcium signalling in mammalian cochlear hair cells
- The role of calcium induced calcium release in hair cell synaptic transmission
- Mechanotransduction in outer hair cells
Diseases related to this field of research
Hearing and balance deficit, deafness, develpomental and drug induced forms of deafness
Processes and functions relevant to this work
Techniques in routine use
Whole-cell patch-clamp electrophysiology, capacitance measurements, confocal calcium imaging, RT-PCR
Equipment in routine use
Electrophysiological equipment, confocal microscope
Prof. Robert Fettiplace - University of Madison Wisconsin USA
- Higher mental function.
- Element Organiser: Auditory Neuroscience: Hearing and Deafness.
- Szalai, R, Maoiléidigh, D, Ke;nnedy, HJ, Cooper, N, Champneys, AR & Homer, ME 2013, Comparison of nonlinear mammalian cochlear-partition models. Journal of the Acoustical Society of America, vol 133.
- Kennedy, HJ 2012, New developments in understanding the mechanisms and function of spontaneous electrical activity in the developing mammalian auditory system. Journal of the association for reserach in otolaryngology, vol 13., pp. 437-445
- Johnson, S, Kennedy, HJ, Holley, M, Fettiplace, R & Marcotti, W 2012, The resting transducer current drives spontaneous activity in prehearing mammalian cochlear inner hair cells.. The Journal of Neuroscience, vol 32., pp. 10479-10483
- Szalai, R, Tsaneva-Atanasova, K, Homer, M, Champneys, A, Kennedy, H & Cooper, N 2011, Nonlinear models of development, amplification and compression in the mammalian cochlea. Philosophical Transactions of the Royal Society A-Mathematical Physical and Engineering Sciences, vol 369(1954)., pp. 4183 - 4204
- Szalai, R, Tsaneva-Atanasova, K, Homer, M, Champneys, A, Kennedy, H & Cooper, N 2011, Nonlinear models of development, amplification and compression in the mammalian cochlea.
- Szalai, R, Champneys, A, Homer, M, Maoileidigh, DO, Kennedy, H & Cooper, N 2011, On the origins of the compressive cochlear nonlinearity.
- Kennedy, H, Evans, M, Crawford, A & Fettiplace, R 2006, Depolarization of cochlear outer hair cells evokes active hair bundle motion by two mechanisms. Journal of Neuroscience, vol 26 (10)., pp. 2757 - 2766
- Helyer, R, Kennedy, H, Davies, D, Holley, M & Kros, C 2005, Development of outward potassium currents in inner and outer hair cells from the embryonic mouse cochlea. Audiology and Neurotology, vol 10 (1)., pp. 22 - 34
- Kennedy, H, Crawford, A & Fettiplace, R 2005, Force generation by mammalian hair bundles supports a role in cochlear amplification. Nature, vol 433 (7028)., pp. 880 - 883
- Kennedy, H, Evans, M, Crawford, A & Fettiplace, R 2003, Fast adaptation of mechanoelectrical transducer channels in mammalian cochlear hair cells. Nature Neuroscience, vol 6 (8)., pp. 832 - 836
Full publications list in the University of Bristol publications system