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Expressions of Aquaporin‐2, Vasopressin Type 2 Receptor, Transient Receptor Potential Channel Vanilloid (TRPV)1, and TRPV4 in the Human Endolymphatic Sac
Author(s) -
Taguchi Daizo,
Takeda Taizo,
Kakigi Akinobu,
Takumida Masaya,
Nishioka Rie,
Kitano Hiroya
Publication year - 2007
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1097/mlg.0b013e318031c802
Subject(s) - transient receptor potential channel , trpv1 , trpv4 , trpv , endolymphatic sac , endocrinology , chemistry , aquaporin 2 , medicine , trpc , microbiology and biotechnology , receptor , anatomy , biology , inner ear , water channel , mechanical engineering , engineering , inlet
Objective : To localize aquaporin (AQP)2, vasopressin type 2 receptor (V 2 ‐R), and transient receptor potential channel vanilloid subfamily 1, 4 (TRPV1, TRPV4) in the human endolymphatic sac (ES). Methods : Three samples of human ES were sampled during the removal of vestibular schwannoma by way of the translabyrinthine approach. The samples were immediately fixed in 4% paraformaldehyde and embedded in OCT compound; immunohistochemistry was performed with AQP2, V 2 ‐R, TRPV1, and TRPV4 polyclonal antibodies. Results : AQP2, V 2 ‐R, TRPV1, and TRPV4 proteins were detected in the epithelial layer of the ES but were not observed in connective tissue around the ES. TRPV1 was also expressed in blood vascular endothelial cells of the connective tissue of ES. Conclusions : AQP2, V 2 ‐R, and TRPV4 were expressed in the luminal epithelium of human ES. The same characteristic distribution of water and ion channels is seen in the kidney, where a significant amount of fluid is filtrated and resorbed. ES probably plays an active role in the homeostasis of the endolymph.