gms | German Medical Science

78. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e. V.

Deutsche Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e. V.

16.05. - 20.05.2007, München

High resolution ultrastructure and regeneration of links after BAPTA treatment in maturing rat auditory hair cells

Meeting Abstract

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German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. 78th Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. Munich, 16.-20.05.2007. Düsseldorf, Köln: German Medical Science; 2007. Doc07hno036

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Veröffentlicht: 8. August 2007

© 2007 Koitschev et al.
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Hair bundles of auditory hair cells are mechanosensitive structures, composed of individual stereocilia, interconnected by fine filaments, called links. Here we show a strong developmental change in cross-link density. Furthermore we demonstrate a maturation dependent vulnerability of the links against the Ca2+-chelator BAPTA and their ability to regenerate within several hours.

Cochlear hair cells in neonatal rats undergo a reorganization of their hair bundle structure prior to the onset of hearing. The maturation progresses from the base to the apex along the organ of Corti. Thus, the most striking effect of BAPTA during development was seen in newborns (postnatal day 0, P0). By Scanning Electron Microscopy (SEM) we found in the apical coil of the early postnatal rat cochlea a dense network of undifferentiated links, which were completely vanished after 30 min. of BAPTA treatment.

More mature OHCs of the medial coil (P0) showed already an adult-like V-shaped bundle with differentiated side and tip links. Here, BAPTA treatment still eliminated both link types. Interestingly, the hair bundle structure wasn't splayed as in apical OHCs. Controls display typical morphology with intact tip and side links. Disruption of links was fully recovered after culturing for 19h, similar to a report in chicken auditory hair cells.

This implicates that at early stage of maturation all links between the stereocilia posses a “tip-link-like” molecular basis. Our findings are in contrast to hair bundles in adult models, where BAPTA selectively disrupts only tip links. This may provide new perspectives to finally unravel the molecular identity and differences between tip and side links.