title: Spiral ganglion outgrowth and hearing development in p75-deficient mice.
abstract: To explore the role of nerve growth factor receptor p75(NTR) during the terminal neuronal development of the mammalian cochlea the onset of hearing and the in vitro response of spiral ganglion neurites to neurotrophin 3 (NT-3), which is known to play a critical role during neonatal inner ear development, were investigated in p75(NTR)-deficient mice (p75(NTR)-/-). Auditory-evoked brain stem response recordings from p75(NTR)-/- and wild-type (WT) littermates were measured from postnatal days (PD) 8 to 23. Additionally, spiral ganglion explants from p75(NTR)-/- and WT animals were dissected and cultured in an organotypic tissue culture system. In both groups, spiral ganglion neurite outgrowth was analyzed with and without NT-3 supplementation. No significant differences in the onset of hearing of mutant mice compared to the WT mice were detected, and both groups showed a similar development of hearing until PD 23. After stimulation with NT-3, neurite outgrowth was enhanced in both p75(NTR)-/- and WT mice. However, neurites from p75(NTR)-/- spiral ganglion explants were longer in both culture conditions. Moreover, NT-3 did not significantly enhance neurite number in p75(NTR)-/-, as it did in WT mice. P75(NTR) has a remarkable influence on spiral ganglion neurite growth behavior. However, p75(NTR) does not seem to be essential for the development of basic hearing function in the first 3 postnatal weeks.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Ruhr-University Bochum, Bochum, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Brors
authors.forename: Stefan
authors.initials: S
authors.lastname: Hansen
authors.forename: Robert
authors.initials: R
authors.lastname: Mlynski
authors.forename: Stefan
authors.initials: S
authors.lastname: Volkenstein
authors.forename: Christoph
authors.initials: C
authors.lastname: Aletsee
authors.forename: Michael
authors.initials: M
authors.lastname: Sendtner
authors.forename: Allen F
authors.initials: AF
authors.lastname: Ryan
authors.forename: Stefan
authors.initials: S
authors.lastname: Dazert
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D006309:Hearing / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D016501:Neurites / Q000187:drug effects / Q000502:physiology*; D020933:Neurotrophin 3 / Q000494:pharmacology; D009924:Organ Culture Techniques; D020800:Receptor, Nerve Growth Factor / Q000235:genetics / Q000502:physiology*; D013136:Spiral Ganglion / Q000166:cytology* / Q000196:embryology* / Q000254:growth & development / Q000502:physiology
chemical_list: D020933:Neurotrophin 3; D020800:Receptor, Nerve Growth Factor