Spiral Ganglion Outgrowth and Hearing Development in p75NTR-Deficient MiceBrors D.a · Hansen S.a · Mlynski R.b · Volkenstein S.a · Aletsee C.b · Sendtner M.c · Ryan A.F.d · Dazert S.a
aDepartment of Otolaryngology, Head and Neck Surgery, Ruhr-University Bochum, Bochum, and Departments of bOtolaryngology, Head and Neck Surgery, and cNeurobiology, Bayerische Julius-Maximilians-University, Würzburg, Germany; dDepartment of Otolaryngology, University of California, San Diego, Calif., USA
To explore the role of nerve growth factor receptor p75NTR 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 p75NTR-deficient mice (p75NTR–/–). Auditory-evoked brain stem response recordings from p75NTR–/– and wild-type (WT) littermates were measured from postnatal days (PD) 8 to 23. Additionally, spiral ganglion explants from p75NTR–/– 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 p75NTR–/– and WT mice. However, neurites from p75NTR–/– spiral ganglion explants were longer in both culture conditions. Moreover, NT-3 did not significantly enhance neurite number in p75NTR–/–, as it did in WT mice. P75NTR has a remarkable influence on spiral ganglion neurite growth behavior. However, p75NTR does not seem to be essential for the development of basic hearing function in the first 3 postnatal weeks.
© 2008 S. Karger AG, Basel
This study was presented at the 27th ARO MidWinter Meeting, Daytona, Fla., USA, 02/24/2004.
D.B. and S.H. contributed equally to this study.
Received: March 21, 2007
Accepted after revision: April 9, 2008
Published online: July 29, 2008
Number of Print Pages : 8
Number of Figures : 3, Number of Tables : 2, Number of References : 34
Audiology and Neurotology (Basic Science and Clinical Research in the Auditory and Vestibulary Systems and Diseases of the Ear)
Vol. 13, No. 6, Year 2008 (Cover Date: October 2008)
Journal Editor: Harris J.P. (San Diego, Calif.)
ISSN: 1420–3030 (Print), eISSN: 1421–9700 (Online)
For additional information: http://www.karger.com/AUD