The gradual arrangement of cells in the organ of Corti in the inner ear is vital for hearing. Kobe University reports.
The organ of Corti is located in the membranous labyrinth of the cochlea. It is he who transforms the sound stimulation into a nerve impulse, so this is a sensor. A structure resembling a chessboard is clearly visible when viewed through a microscope. Hair cells that transmit sound waves to the brain are separated by support cells that prevent hair cells from touching each other. Although this bewilderment was believed to be necessary for the proper functioning of the organ of Corti, the relationship between this pattern and hearing function remained unclear for a long time.
The Japanese scientists found that this pattern is due to the fact that hair cells and supporting cells express different types of nectin protein molecules with different cell adhesion. This causes the hair cell and supporting cell to bind to each other more strongly than two hair cells or two support cells. During the experiment on mice, the scientists turned off the expression of one of the nectin species (nectin-3), so the chess structure could not be formed.
Despite the fact that the total number of hair cells in the organs of Corti was the same at birth, such mice appeared to develop partial deafness. The scientists then performed an autopsy on the one-month-old mice and found that about half of the hair cells were lost. Especially often the cells that stuck together died.
Thus, the authors conclude that the chessboard-like structure in the ear is a key condition for the functioning of hearing.