Observation of the attachment of the tectorial membrane to the surface of the organ of Corti in the neonatal hamster

Abstract

Morphological developmental change of the attachment of the tectorial membrane to the surface of the organ of Corti in the neonatal hamster was studied.Golden hamsters were decapitated under ether anesthesia everyday from the day of birth until 20 days after birth. The inner ears were extirpated within 10 minutes in chilled 1% paraformaldehyde-3% glutaraldehyde solution. All specimens were refixed in 2% osmic acid, dehydrated and observed by scanning electron microscope with the styrene resin cracking method.As a result, the following conclusions were obtained. 1) In the immature organ of Corti on the day of birth, marginal complex of the tectorial membrane is noted as an amorphous substance on the supporting cells surrounding sensory cells. 2) From 3 days after birth, marginal complex forms a network and the attachments of the membranous part to the surface of pillar cells, radial strands to the surface of each rows of Deiters' cells and oblique strands to the basal direction to the surface of Hensen's cells begin to be observed. These attachments gradually disappear from about a week after birth when marginal pillars appear on the surface of the third row of Deiters' cells. 3) Marginal pillars begin to disappear on 16 days after birth and are not observed on 20 days after birth at all. 4) The imprints of the sensory hairs of the outer hair cells on the undersurface of the tectorial membrane are clearly observed from about two weeks after birth. 5) It seems that the sensory hairs of the inner hair cells do not make an attachment to the tectorial membrane in the normal condition. 6) It seems that though the attachment of the tectorial membrane (Hensen's stripe) to the surface of supporting cells surrounding inner hair cells exists in the developing stage, it is much weaker than the attachment in other parts. 7) Considering the findings from other mammals reported by other investigators, it seems that the disappearance of marginal pillars indicates maturity of the organ of Corti.