Jpn. J. Pharmacol. 83 (3), 233-240 (2000)

Immunohistochemical Demonstration of Cl^- Pump in Type A Intercalated Cells of Rat Kidney

Toshiaki Higashida¹, Xun-Ting Zeng¹, Mitsuyoshi Hara¹, Koichiro Omori², Sei Sasaki³, Michiaki Orikasa⁴,
Fujio Shimizu⁴ and Chiyoko Inagaki^1,*


¹Departmentﾊof Pharmacology and ²Department of Physiology, Kansai Medical University, Moriguchi, Osaka 570-8506, Japan
³SecondﾊInternal Medicine, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
⁴Departmentﾊof Cell Biology, Institute of Nephrology, Niigata University School of Medicine, Niigata 951-8510, Japan
*ﾊTo whom correspondence should be addressed.

Abstract: In order to demonstrate the localization of an ethacrynic acid-sensitive Cl^- pump in the rat kidney, immunohistochemical analysis was performed using an anti-Cl^- pump antibody raised against rat brain Cl^- pump protein with confocal laser scanning microscopy. The antibodies against Na⁺,K⁺-ATPase, aquaporinﾊ2 and a typeﾊB intercalated cell marker, 43-kDa protein, were also used for comparison. Anti-Cl^- pump antibody recognized a 51-kDa renal protein of the same size as that in the brain on Western blots. Cl^--pump-like immunoreactivity was observed on the basolateral membranes of 42ﾊｱﾊ3% of cortical collecting duct (CCD) cells and of 38ﾊｱﾊ1% of outer medullar collecting duct (OMCD) cells. Such immunoreactivity in CCD was sometimes co-localized with Na⁺,K⁺-ATPase, but in OMCD, the Cl^- pump-like immunoreactivity co-existed with neither Na⁺,K⁺-ATPase, aquaporinﾊ2 nor the typeﾊB intercalated cell marker 43-kDa protein. Thus, the Cl^- pump was demonstrated to be localized on the basolateral membranes of typeﾊA intercalated cells of cortical and medullary collecting ducts in the rat kidney.

Keywords: Cl^- pump, Ethacrynic acid, Intercalated cell, Collecting duct, Kidney