Expression of transient receptor potential channel mucolipin (TRPML) and polycystine (TRPP) in the mouse inner ear.

CONCLUSIONS: TRPML3 may play distinct roles in the inner ear, such as stereociliar organization, sensory cell transduction, and inner ear fluid homeostasis, and TRPP3 may be important for fluid homeostasis in the inner ear.

OBJECTIVE: To study the expression of TRPML1-3 and TRPP2, 3, and 5 in the mouse inner ear.

MATERIALS AND METHODS: Localization of TRPML1-3 and TRPP2, 3, and 5 in the inner ear of CBA/J mice was investigated by immunohistochemistry.

RESULTS: TRPML1-3 immunoreactivity was evident in the stria vascularis, spiral prominence, and spiral ligament. TRPML immunoreactivity was also observed in outer and inner hair cells, supporting cells, and spiral ganglion cells. The vestibular end organs, vestibular sensory cells, dark cells, and ganglion cells all showed immunoreactivity to TRPML. TRPP2 immunoreactivity was evident in the outer lining of the lateral wall of the cochlea, spiral ganglion cells, vestibular sensory cells, and ganglion cells. TRPP3 immunoreactivity was present in stria vascularis, spiral ganglion cells, vestibular sensory cells, dark cells, and ganglion cells. Faint TRPP5 immunoreactivity was observed in the spiral ganglion cells and vestibular ganglion cells.