Functional expression of transient receptor potential vanilloid 4 in the mouse cochlea.
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.
Shen
Jing
J
Hearing Research Laboratory, Department of Otolaryngology, Kansai Medical University, Moriguchi, Japan.
Harada
Narinobu
N
Kubo
Nobuo
N
Liu
Bing
B
Mizuno
Atsuko
A
Suzuki
Makoto
M
Yamashita
Toshio
T
D000818:Animals; D015152:Blotting, Northern / Q000379:methods; D015153:Blotting, Western / Q000379:methods; D002118:Calcium / Q000378:metabolism; D002614:Chelating Agents / Q000494:pharmacology; D003051:Cochlea / Q000166:cytology* / Q000378:metabolism*; D004347:Drug Interactions; D004533:Egtazic Acid / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology*; D007038:Hypotonic Solutions / Q000494:pharmacology; D007150:Immunohistochemistry / Q000379:methods; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010704:Phorbols / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012430:Ruthenium Red / Q000378:metabolism; D050916:TRPV Cation Channels / Q000172:deficiency / Q000502:physiology*
D002614:Chelating Agents; D007038:Hypotonic Solutions; D010704:Phorbols; D012333:RNA, Messenger; D050916:TRPV Cation Channels; C486576:Trpv4 protein, mouse; D012430:Ruthenium Red; D004533:Egtazic Acid; D002118:Calcium; C033085:phorbol