Force generation in the outer hair cell of the cochlea.
AUTOR(ES)
Iwasa, K H
RESUMO
The outer hair cell of the mammalian cochlea has a unique motility directly dependent on the membrane potential. Examination of the force generated by the cell is an important step in clarifying the detailed mechanism as well as the biological importance of this motility. We performed a series of experiments to measure force in which an elastic probe was attached to the cell near the cuticular plate and the cell was driven with voltage pulses delivered from a patch pipette under whole-cell voltage clamp. The axial stiffness was also determined with the same cell by stretching it with the patch pipette. The isometric force generated by the cell is around 0.1 nN/mV, somewhat smaller than 0.15 nN/mV, predicted by an area motor model based on mechanical isotropy, but larger than in earlier reports in which the membrane potential was not controlled. The axial stiffness obtained, however, was, on average, 510 nN per unit strain, about half of the value expected from the mechanical isotropy of the membrane. We extended the area motor theory incorporating mechanical orthotropy to accommodate the axial stiffness determined. The force expected from the orthotropic model was within experimental uncertainties.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1180953Documentos Relacionados
- Ionic currents of outer hair cells isolated from the guinea-pig cochlea.
- Variation in expression of the outer hair cell P2X receptor conductance along the guinea-pig cochlea.
- Control of intracellular calcium by ATP in isolated outer hair cells of the guinea-pig cochlea.
- Action of salicylate on membrane capacitance of outer hair cells from the guinea-pig cochlea.
- Cellular mechanism of acetylcholine-induced response in dissociated outer hair cells of guinea-pig cochlea.