Displacement of the reticular lamina with and without the tectorial membrane in the guinea pig cochlea.
OBJECTIVE
In an attempt to establish the mechanical relationships between the reticular lamina and tectorial membrane, we studied the morphological changes of the reticular lamina on a micrometer scale when an in vitro preparation of guinea pig cochlea with and without tectorial membrane was exposed to a potassium-rich medium.


METHODS
Using video-enhanced differential interference contrast microscopy, the radial displacement of the inner hair cells (IHCs) and outer hair cells (OHCs) in the reticular lamina was measured in real time after exposure to the potassium-rich medium for 3 min.


RESULTS
The amplitude of the displacement of the OHCs in preparations with an intact tectorial membrane was half of that observed in those in which the tectorial membrane had been removed. A similar displacement response was also observed for the IHCs, although it was smaller than that for the OHCs. There was no significant difference in the amplitude of the displacement among the three rows of OHCs.


CONCLUSIONS
These results suggest that the structure linking the OHCs to the pillar cells is very elastic and that the movement of the OHCs in situ is weakly mechanically coupled to the IHCs. The tectorial membrane provides increased compliance in the motion of the IHCs and OHCs.
Sakai
Takeo
T
Department of Otolaryngology, Hamamatsu University School of Medicine, Hamamatsu, Japan. sakaijibi@aol.com
Iwasaki
Satoshi
S
Hoshino
Tomoyuki
T
Terakawa
Susumu
S
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001485:Basement Membrane / Q000378:metabolism* / Q000648:ultrastructure; D001696:Biomechanical Phenomena; D003051:Cochlea / Q000378:metabolism*; D006168:Guinea Pigs; D006198:Hair Cells, Auditory / Q000378:metabolism* / Q000648:ultrastructure; D018715:Microscopy, Video; D011188:Potassium / Q000008:administration & dosage / Q000493:pharmacokinetics; D012155:Reticulin / Q000378:metabolism* / Q000648:ultrastructure; D013680:Tectorial Membrane / Q000378:metabolism* / Q000648:ultrastructure
D012155:Reticulin; D011188:Potassium