Immunohistochemical localization of ph-sensitive k+ channel; ractk1. Suzuki, Makoto, Toshihiro Takigawa, Kenjirou Kimura, Chizuko Koseki, and Masashi Imai. Department of Pharmacology, Department of Anatomy, Jichi Medical School, Tochigi, 329-04, Japan, Internal Medicine II, Tokyo University, Tokyo, Japan.
APStracts 2:0099C, 1995.
RACTK1 cDNA encodes a pH-sensitive K+ channel from the renal cortical collecting tubule cells which is only localized in the kidney by northern blots [1]. We further investigated the localization of the channel by immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR). Immunohistochemical analysis showed that the signal was detected in various epithelia including the luminal membrane of the cortical collecting tubules, artery of the kidney and pancreatic ducts. Interestingly, the signal was also detected in the coronary vascular smooth muscle and cerebral artery. These tissue distributions were confirmed by localization of mRNA determined by RT-PCR. These findings suggest that RACTK1 encoding pH -sensitive K channel are widely distributed in epithelia as well as in vascular smooth muscle cells.

Received 6 September 1994; accepted in final form 3 February
1995.
APS Manuscript Number C527-4.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 28 February 1995.