Functional expression of transient receptor potential vanilloid 4 in the mouse cochlea

• Published in: Neuroreport Vol. 17; no. 2; p. 135
• Main Authors: Shen, Jing, Harada, Narinobu, Kubo, Nobuo, Liu, Bing, Mizuno, Atsuko, Suzuki, Makoto, Yamashita, Toshio
• Format: Journal Article
• Language: English
• Published: England 06.02.2006
• Subjects: Animals; Blotting, Northern - methods; Blotting, Western - methods; Calcium - metabolism; Chelating Agents - pharmacology; Cochlea - cytology; Cochlea - metabolism; Drug Interactions; Egtazic Acid - pharmacology; Gene Expression Regulation - genetics; Gene Expression Regulation - physiology; Hypotonic Solutions - pharmacology; Immunohistochemistry - methods; Mice; Mice, Inbred C57BL; Mice, Knockout; Neurons - drug effects; Neurons - metabolism; Phorbols - pharmacology; Reverse Transcriptase Polymerase Chain Reaction - methods; RNA, Messenger - biosynthesis; Ruthenium Red - metabolism; TRPV Cation Channels - deficiency; TRPV Cation Channels - physiology
• ISSN: 0959-4965
• DOI: 10.1097/01.wnr.0000199459.16789.75

Transient receptor potential vanilloid 4, the Ca2+-permeable cation channel has been proposed as an osmosensitive and a mechanosensitive channel. We investigated functional expression of transient receptor potential vanilloid 4 in inner hair cells, outer hair cells, and spiral ganglion neurons of the mouse cochlea. Transient receptor potential vanilloid 4 mRNA and protein were expressed in inner hair cells, outer hair cells, and spiral ganglion neurons on the basis of the findings of reverse transcriptase-polymerase chain reaction, single-cell reverse transcriptase-polymerase chain reaction, and immunohistochemistry, whereas they were negative in transient receptor potential vanilloid 4-/- mice cochleae. Hypotonic stimulation and 4-alpha-phorbol 12,13-didecanoate, a transient receptor potential vanilloid 4 synthetic activator, increased the intracellular Ca2+ concentrations in wild-type outer hair cells, whereas in transient receptor potential vanilloid 4-/- mice, outer hair cells failed to exhibit a Ca2+ response to both stimulations. In conclusion, transient receptor potential vanilloid 4 may function as an osmosensory and a mechanosensory receptor in the cochlea.