Bitte benutzen Sie diese Referenz, um auf diese Ressource zu verweisen: doi:10.22028/D291-40131
Titel: Fast Ca2+ Transients of Inner Hair Cells Arise Coupled and Uncoupled to Ca2+ Waves of Inner Supporting Cells in the Developing Mouse Cochlea
VerfasserIn: Eckrich, Tobias
Blum, Kerstin
Milenkovic, Ivan
Engel, Jutta
Sprache: Englisch
Titel: Frontiers in Molecular Neuroscience
Bandnummer: 11
Verlag/Plattform: Frontiers
Erscheinungsjahr: 2018
Freie Schlagwörter: cochlea
spontaneous activity
development
Ca2+ wave
inner hair cell
CaV1.3
DDC-Sachgruppe: 610 Medizin, Gesundheit
Dokumenttyp: Journalartikel / Zeitschriftenartikel
Abstract: Before the onset of hearing, which occurs around postnatal day 12 (P12) in mice, inner hair cells (IHCs) of the immature cochlea generate sound-independent Ca2+ action potentials (APs), which stimulate the auditory pathway and guide maturation of neuronal circuits. During these early postnatal days, intercellular propagating Ca2+ waves elicited by ATP-induced ATP release are found in inner supporting cells (ISCs). It is debated whether IHCs are able to fire Ca2+ APs independently or require a trigger by an ISC Ca2+ wave. To identify the Ca2+ transients of IHCs underlying Ca2+ APs and to analyze their dependence on ISC Ca2+ waves, we performed fast Ca2+ imaging of Fluo-8 AM-loaded organs of Corti at P4/P5. Fast Ca2+ transients (fCaTs) generated by IHCs were simultaneously imaged with Ca2+ waves in ISCs. ISC Ca2+ waves frequently evoked bursts consisting of >5 fCaTs in multiple adjacent IHCs. Although Ca2+ elevations of small amplitude appeared to be triggered by ISC Ca2+ waves in IHCs of Cav1.3 knockout mice we never observed fCaTs, indicating their requirement for Ca2+ influx through Cav1.3 channels. The Ca2+ wave-triggered Ca2+ upstroke in wildtype IHCs occurred 0.52 ± 0.27 s later than the rise of the Ca2+ signal in the adjacent ISCs. In comparison, superfusion of 1 µM ATP elicited bursts of fCaTs in IHCs starting 0.99 ± 0.34 s prior to Ca2+ elevations in adjacent ISCs. PPADS irreversibly abolished Ca2+ waves in ISCs and reversibly reduced fCaTs in IHCs indicating differential involvement of P2 receptors. IHC and ISC Ca2+ signals were however unaltered in P2X2R/P2X3R double knockout or in P2X7R knockout mice. Together, our data revealed a fairly similar occurrence of fCaTs within a burst (56.5%) compared with 43.5% as isolated single fCaTs or in groups of 2–5 fCaTs (minibursts). We provide evidence that IHCs autonomously generate single fCaTs and minibursts whereas bursts synchronized between neighboring IHCs were mostly triggered by ISC Ca2+ waves. Neonatal IHCs thus spontaneously generate electrical and Ca2+ activity, which is enhanced and largely synchronized by activity of ISCs of Kölliker’s organ indicating two sources of spontaneous activity in the developing auditory system.
DOI der Erstveröffentlichung: 10.3389/fnmol.2018.00264
URL der Erstveröffentlichung: https://www.frontiersin.org/articles/10.3389/fnmol.2018.00264
Link zu diesem Datensatz: urn:nbn:de:bsz:291--ds-401310
hdl:20.500.11880/36124
http://dx.doi.org/10.22028/D291-40131
ISSN: 1662-5099
Datum des Eintrags: 17-Jul-2023
Fakultät: M - Medizinische Fakultät
Fachrichtung: M - Biophysik
Professur: M - Prof. Dr. Jutta Engel
Sammlung:SciDok - Der Wissenschaftsserver der Universität des Saarlandes

Dateien zu diesem Datensatz:
Datei Beschreibung GrößeFormat 
fnmol-11-00264.pdf7,62 MBAdobe PDFÖffnen/Anzeigen


Diese Ressource wurde unter folgender Copyright-Bestimmung veröffentlicht: Lizenz von Creative Commons Creative Commons