Analysis of outer hair cell motility and force productioin using shell theory

It is considered that the vibration of the basilar membrane is amplified by the force which is accompanied with the motility of the outer hair cell (OHC). The OHC motility is estimated to be due to the deformation of the motor protein, which distributes along the OHC lateral wall, and it is speculated that the mechanical properties of the cell lateral wall and distribution of the motor protein are related to the force production of the OHC. Therefore, in this study, the OHC model (Fig. 1) is constructed using shell theory, and the force produced by the cell is analyzed.
Fig. 2(a) shows the numerical result of the force production of the OHC. When the stiffness of the cell lateral wall and the distribution of the motor protein shown in Table 1 are taken into consideration in the model, it is clear that the shorter cell can produce larger force. It is known that the shorter cells locate in the basal end of the cochlea, where the stiffness of the basilar membrane is large (Fig. 2(b)). Therefore, it is estimated that the OHC can produce the force effectively in the cochlea.

Figure 1. Outer hair cell
(a) Longitudinal section which is observed using transmission electron microscope (Saito, 1983). (b) Cylindrical shell model. In the model, the lateral wall of the OHC is treated as an orthotropic one layer shell.

Table 1. Stiffness of the OHC lateral wall and the density of the motor protein

Figure 2. Effect of the cell length on force production of the OHC.
(a) Force produced by the OHC. The difference in the mechanical properties of the cell lateral wall and that in the density of the protein motor accompanied by the difference in the cell length (Table 1) are taken into consideration to the analysis. (b) Distribution of the basilar membrane stiffness, OHC length and force produced by the OHC

| Back || Home |