Wilms, Viviane and Köppl, Christine and Söffgen, Chris and Hartmann, Anna-Maria and Nothwang, Hans Gerd (2016) Molecular bases of K+ secretory cells in the inner ear: shared and distinct features between birds and mammals. Scientific Reports, 6 (1). ISSN 2045-2322

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Abstract

In the cochlea, mammals maintain a uniquely high endolymphatic potential (EP), which is not observed in other vertebrate groups. However, a high [K+] is always present in the inner ear endolymph. Here, we show that Kir4.1, which is required in the mammalian stria vascularis to generate the highly positive EP, is absent in the functionally equivalent avian tegmentum vasculosum. In contrast, the molecular repertoire required for K+ secretion, specifically NKCC1, KCNQ1, KCNE1, BSND and CLC-K, is shared between the tegmentum vasculosum, the vestibular dark cells and the marginal cells of the stria vascularis. We further show that in barn owls, the tegmentum vasculosum is enlarged and a higher EP (~+34 mV) maintained, compared to other birds. Our data suggest that both the tegmentum vasculosum and the stratified stria vascularis evolved from an ancestral vestibular epithelium that already featured the major cell types of the auditory epithelia. Genetic recruitment of Kir4.1 specifically to strial melanocytes was then a crucial step in mammalian evolution enabling an increase in the cochlear EP. An increased EP may be related to high-frequency hearing, as this is a hallmark of barn owls among birds and mammals among amniotes.

Item Type:	Article
Additional Information:	Publiziert mit Hilfe des DFG-geförderten Open Access-Publikationsfonds der Carl von Ossietzky Universität Oldenburg.
Uncontrolled Keywords:	Evolution, Inner ear, Molecular biology, endolymphatic potential (EP)
Subjects:	Science and mathematics Science and mathematics > Life sciences, biology Science and mathematics > Animals (zoology)
Divisions:	Faculty of Medicine and Health Sciences > Department of Neuro Sciences
Date Deposited:	20 Sep 2017 08:30
Last Modified:	20 Sep 2017 08:30
URI:	https://oops.uni-oldenburg.de/id/eprint/3271
URN:	urn:nbn:de:gbv:715-oops-33524
DOI:	doi:10.1038/srep34203
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