Expression of aquaporins, vasopressin type 2 receptor, and Na+₋K+₋Cl⁻ cotransporters in the rat endolymphatic sac.
CONCLUSIONS
Since many water channels and pumps, such as aquaporin (AQP) 1-4, AQP6-9, vasopressin type 2 receptor (V(2)-R), Na(+)-K(+)-Cl(-) cotransporter (NKCC) 1, and NKCC2 were expressed in the rat endolymphatic sac, it should play an important role in the physiological function of acid-based metabolism and water balance in endolymphatic fluid homeostasis.


OBJECTIVE
To evaluate the expression and immunolocalization of AQP1-9, V(2)-R, NKCC1, and NKCC2 in the rat endolymphatic sac.


METHODS
Wistar rats were used. Expression of AQP1-9, V(2)-R, NKCC1, and NKCC2 mRNA in the rat endolymphatic sac was investigated using the reverse transcription-polymerase chain reaction (RT-PCR) method, and detailed immunolocalization of AQP1-9, V(2)-R, NKCC1, and NKCC2 was investigated using immunohistochemical methods, including immunofluorescence microscopy.


RESULTS
mRNAs and proteins of AQP1-4, AQP6-9, V(2)-R, NKCC1, and NKCC2 were expressed, but AQP5 was not expressed in the rat endolymphatic sac.
Department of Otolaryngology, Kochi Medical School, Kochi, Japan. jm-nishimuram@kochi-u.ac.jp
Masahiko
M
Nishimura
Akinobu
A
Kakigi
Taizo
T
Takeda
Setsuko
S
Takeda
Katsumi
K
Doi
D000818:Animals; D020346:Aquaporins / Q000378:metabolism*; D004712:Endolymphatic Sac / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017483:Receptors, Vasopressin / Q000378:metabolism*; D028021:Sodium-Potassium-Chloride Symporters / Q000378:metabolism*; D014882:Water-Electrolyte Balance
D020346:Aquaporins; D012333:RNA, Messenger; D017483:Receptors, Vasopressin; D028021:Sodium-Potassium-Chloride Symporters