Caelers A Monge A Michael J Schwab ME Bodmer D 2009 HYPOTHESIS Different members of the Nogo system are expressed in the mammalian cochlea. BACKGROUND The protein Nogo has gained a lot of attention during the last couple of years because it inhibits neurite outgrowth in the adult central nervous system. In contrast to the central nervous system, very little is known regarding the expression and possible function of the Nogo system within the inner ear. METHODS Using reverse-transcriptase-polymerase chain reaction and immunohistochemistry, we analyzed for the expression of members of the Nogo system within the cochlea. In addition, we determined hearing levels of Nogo A knockout and wild-type mice with auditory brainstem response audiometry. RESULTS In this study, we demonstrate the expression of Nogo A, B, C, and of Nogo receptor mRNA in the organ of Corti, spiral ganglion, and stria vascularis. Immunohistochemistry revealed that Nogo A and Nogo receptor localize to the spiral ganglion neurons. Interestingly, Nogo A expression was also observed in the outer and inner hair cells of the organ of Corti. As revealed by light microscopy, deletion of Nogo A does not alter cochlear microanatomy. We have assessed hearing levels in 10-month old wild-type and Nogo A knockout mice, and thereby, we could not detect any differences between these 2 groups. CONCLUSION Different members of the Nogo family are expressed in the mammalian cochlea. Deletion of Nogo A does not alter cochlea microanatomy or hearing levels compared with wild-type mice. https://sonar.ch/global/documents/98215 eng info:eu-repo/semantics/altIdentifier/doi/10.1097/MAO.0b013e3181ab95c5 info:eu-repo/semantics/altIdentifier/pmid/19546827 Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. - 2009 Acoustic Stimulation Animals Audiometry Auditory Threshold Cochlea Fluorescent Antibody Technique Hair Cells, Vestibular Hearing Loss Immunohistochemistry Mammals Mice Mice, Inbred C57BL Mice, Knockout Myelin Proteins Nogo Proteins Organ Culture Techniques RNA Rats Rats, Sprague-Dawley Reverse Transcriptase Polymerase Chain Reaction Nogo in the Mammalian cochlea. http://purl.org/coar/resource_type/c_6501