Mechanical Relaxation of the Hair Bundle Mediates Adaptation in Mechanoelectrical Transduction by the Bullfrog's Saccular Hair Cell
Abstract
Mechanoelectrical transduction by hair cells of the frog's internal ear displays adaptation: the electrical response to a maintained deflection of the hair bundle declines over a period of tens of milliseconds. We investigated the role of mechanics in adaptation by measuring changes in hair-bundle stiffness following the application of force stimuli. Following step stimulation with a glass fiber, the hair bundle of a saccular hair cell initially had a stiffness of ≈ 1 mN\cdot m-1. The stiffness then declined to a steady-state level near 0.6 mN\cdot m-1 with a time course comparable to that of adaptation in the receptor current. The hair bundle may be modeled as the parallel combination of a spring, which represents the rotational stiffness of the stereocilia, and a series spring and dashpot, which respectively, represent the elastic element responsible for channel gating and the apparatus for adaptation.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- May 1987
- DOI:
- 10.1073/pnas.84.9.3064
- Bibcode:
- 1987PNAS...84.3064H