Calcium channels in the inner hair cells
Deafness Research UK awarded a grant to Dr Walter Marcotti at the University of Sheffield to investigate the process of transforming sound into electrical signals to be interpreted by the brain.
[Small grant: 2007-2008]
The mammalian cochlea is the sensory organ responsible for the detection of sound over a large range of intensity and frequency (pitch). This is possible mainly because sound is transformed inside the cochlea by extremely sensitive sensory receptors named hair cells. The name hair cell derives from the hair-like elements (stereocilia) that project from the top of the cell.
During sound stimulation, minute vibration of the stereocilia – in the range of nanometres – initiates the conversion of sound into an electrical signal that is relayed to the brain via auditory nerve fibres. Before the signal reaches the auditory fibres it is shaped by the effects of various chemical signals that enter or exit the cell via tube-like channels present in the cell membrane.
Neurotransmitters are specific molecules that are used by hair cells and neurons to communicate. The release of neurotransmitter from hair cells is finely controlled by calcium channels in their cell membrane. Therefore the research team’s aim was to understand how calcium channels function and to find out how they are distributed in hair cells along the cochlea.
The purpose of the study was to improve, at a molecular level, our understanding of how information gathered by single hair cells about the frequency, intensity and timing of sound, can be faithfully passed onto auditory fibres.
Results from the present study are currently in the final stages of analysis and preparation to be published in a scientific journal.
Dr Marcotti recently published some of his findings on calcium channels from an earlier project supported by Deafness Research UK. Click on the following link to read about the results:
