Expression of aquaporins, vasopressin type 2 receptor, and Na+-K+-Cl– cotransporters in the rat endolymphatic sac

Abstract

Conclusion. Since many water channels and pumps, such as aquaporin (AQP) 1–4, AQP6–9, vasopressin type 2 receptor (V2-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, V2-R, NKCC1, and NKCC2 in the rat endolymphatic sac. Materials and methods. Wistar rats were used. Expression of AQP1–9, V2-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, V2-R, NKCC1, and NKCC2 was investigated using immunohistochemical methods, including immunofluorescence microscopy. Results. mRNAs and proteins of AQP1–4, AQP6–9, V2-R, NKCC1, and NKCC2 were expressed, but AQP5 was not expressed in the rat endolymphatic sac.