(a) A model of hair cell excitation without OHC motility
according to Davis (17) (see text for details). (b) OHCs
contract when depolarized and the BM is drawn to the reticular lamina.
(c) Experimental arrangement with laser diode beam.
(d) Transverse section through the organ of Corti in the
15.5-kHz region based on measurements made in vivo and
from histological sections: scale bar referenced to the bony edge of
the spiral lamina. Solid horizontal bars indicate the following regions
across the BM width with respect to the bony edge of the spiral lamina:
30–50 μm (junction of inner and outer pillar cells), 60–70 μm
(near midpoint of OPC base), 80–120 μm (Deiters' cells). TM,
tectorial membrane; IHC, inner hair cell; OHC, outer hair cell; HC,
Hensen cell; CC, Claudius cell region; PCs, pillar cells; IPC, inner
pillar cell; OPC, outer pillar cell; DC, Deiters' cell; RL, reticular
lamina; TC, tunnel of Corti. Experiments were performed on deeply
anaesthetized pigmented guinea pigs (180–300 g, 0.06 mg atropine
sulfate s.c., 30 mg/kg pentobarbitone i.p., 4 mg/kg
Droperidol i.m.; 1 mg/kg Phenoperidine i.m.), which were
tracheotomized, artificially respired, and with core temperatures
maintained at 37°C. Modified from Nilsen and Russell (22).