Direct analysis of the variability of the particles located in the lateral membrane of the outer hair cells and transduction mechanism using atomic force microscopy

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 12671646
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Otorhinolaryngology
• Research Institution: Tohoku University
• Principal Investigator: KOIKE Takuji Graduate School of Engineering, Tohoku Univ., Lecturer, 大学院・工学研究科, 講師 (10282097)
• Project Period (FY): 2000 – 2001
• Keywords: cochlear outer hair cell / cytoskeleton / electromotility / atomic force microscopy

Research Abstract

The ultrastructure of the OHC lateral wall was investigated by atomic force microscopy. When the position along the cell axis is represented by the normalized distance from the basal end and the positions of the basal and apical ends are expressed by 0.0 and 1.0, the following conclusions can be drawn.
1. The tapping mode imaging was used in the experiments, because frictional forces are minimized. The particles located in the plasma membrane were not able to be detected. Instead, circumferential filaments were observed, which appear to be actins that are part of the cortical lattice.
2. The mean interval of the circumferential filaments in the region between 0.0 and 0.85 from the basal end and that in the region between 0.85 and 1.0 from the basal end are 54 nm and 44 nm, respectively.
3. The difference between the intervals of the circumferential filaments in the region between 0.0 and 0.85 and between 0.85 and 1.0 from the basal end is one factor that causes the high stiffness in the apical region of the cell.