Expression of the Na+-K+-2Cl- cotransporter in the rat endolymphatic sac.
The endolymphatic sac (ES) is a part of the membranous labyrinth that contains the cochlea, vestibular organs, an d semicircular canals, and is believed to absorb endolymphatic fluid. Na(+)-K(+)-2Cl(-) (NKCC) is a cotransporter that occurs as two isoforms (NKCC-1 and NKCC-2). Especially, NKCC-2 is suggested to participate in ES endolymph absorption. In the present study, the expression and cellular localization of NKCC-1 and NKCC-2 in the rat ES wer e examined by RT-PCR and in situ hybridization, respectively. The findings indicate that both NKCC-1 and NKCC-2 are expressed in the rat ES and suggest that NKCC is involved in ES homeostasis. NKCC-2 may be particularly involved in endolymph absorption. This is the first report confirming NKCC expression in the ES.
Akiyama
Kosuke
K
Department of Otolaryngology, Faculty of Medicine, Kagawa University, Kita-gun Miki-cho Ikenobe 1750-1 , Kagawa 761-0793, Japan.
Miyashita
Takenori
T
Mori
Terushige
T
Mori
Nozomu
N
D000818:Animals; D004712:Endolymphatic Sac / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics*; D017403:In Situ Hybridization; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D028021:Sodium-Potassium-Chloride Symporters / Q000235:genetics / Q000378:metabolism*; D064466:Solute Carrier Family 12, Member 1; D064506:Solute Carrier Family 12, Member 2
D012333:RNA, Messenger; C578716:Slc12a1 protein, rat; C578879:Slc12a2 protein, rat; D028021:Sodium-Potassium-Chloride Symporters; D064466:Solute Carrier Family 12, Member 1; D064506:Solute Carrier Family 12, Member 2