AJP - Renal Watch the video to learn how APS reaches out to developing nations.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Renal Physiol 285: F1149-F1159, 2003. First published August 26, 2003; doi:10.1152/ajprenal.00112.2003
0363-6127/03 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
285/6/F1149    most recent
00112.2003v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (11)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kaewmokul, S.
Right arrow Articles by Wright, S. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kaewmokul, S.
Right arrow Articles by Wright, S. H.

Functional mapping of rbOCT1 and rbOCT2 activity in the S2 segment of rabbit proximal tubule

Santi Kaewmokul,1,2 Varanuj Chatsudthipong,1 Kristen K. Evans,2 William H. Dantzler,2 and Stephen H. Wright2

1Department of Physiology, Mahidol University, Bangkok, 10700 Thailand; and 2Department. of Physiology, University of Arizona, Tucson, Arizona 85724

Submitted 21 March 2003 ; accepted in final form 23 August 2003

A strategy was developed to determine the distribution of activity mediated by the organic cation (OC) transporters OCT1 and OCT2 in rabbit renal proximal tubule (RPT). Both transporters displayed similar affinities for tetraethylammonium (TEA; in CHO-K1 cells, TEA concentrations that resulted in half-maximal transport were 19.9 and 34.5 µM for OCT1 and OCT2, respectively). Similarly, some OCs showed little capacity to discriminate between the two processes (IC50 values for ephedrine of 13.6 and 24.2 µM for OCT1 and OCT2, respectively). However, OCT2 had a higher affinity for cimetidine and [2-(4-nitro-2,1,3-benzoxadiazol-7-yl) aminoethyl]trimethylammonium (NBD-TMA; 1.3 and 1.4 µM, respectively) than did OCT1 (97.3 and 108 µM, respectively). Conversely, OCT1 had a higher affinity for tyramine and pindolol than did OCT2 (21.2 and 2.4 vs. 361 and 50 µM, respectively). We designated these as discriminatory inhibitors and used them to determine the relative contribution of OCT1 and OCT2 for TEA transport in single S2 segments of rabbit RPT. Cimetidine and NBD-TMA were high-affinity inhibitors of TEA transport in S2 segments (median IC50 values of 12.3 and 1.4 µM, respectively); in comparison, tyramine and pindolol were low-affinity inhibitors (265 and 69.3 µM, respectively). These IC50 values were sufficiently close to those for OCT2 to support the conclusion that TEA transport in the S2 segment of rabbit RPT is dominated by OCT2. However, the profile of inhibition of tyramine (an OCT1-selective substrate) transport in single S2 segments indicated that, despite a comparatively low level of expression, OCT1 can play a dominant role in the uptake of selected OC substrates.

organic cation; transport; tetraethylammonium; cimetidine; kidney


Address for reprint requests and other correspondence: S. H. Wright, Dept. of Physiology, College of Medicine, Univ. of Arizona, Tucson, AZ 85724 (E-mail: shwright{at}u.arizona.edu).




This article has been cited by other articles:


Home page
 Am. J. Physiol. Renal Physiol.Home page
S. Soodvilai, A. Chatsudthipong, and V. Chatsudthipong
Role of MAPK and PKA in regulation of rbOCT2-mediated renal organic cation transport
Am J Physiol Renal Physiol, July 1, 2007; 293(1): F21 - F27.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
M. R. Rheault, D. M. Debicki, and M. J. O'Donnell
Characterization of tetraethylammonium uptake across the basolateral membrane of the Drosophila Malpighian (renal) tubule
Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2005; 289(2): R495 - R504.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Renal Physiol.Home page
X. Zhang, C. E. Groves, A. Bahn, W. M. Barendt, M. D. Prado, M. Rodiger, V. Chatsudthipong, G. Burckhardt, and S. H. Wright
Relative contribution of OAT and OCT transporters to organic electrolyte transport in rabbit proximal tubule
Am J Physiol Renal Physiol, November 1, 2004; 287(5): F999 - F1010.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Renal Physiol.Home page
S. H. Wright, K. K. Evans, X. Zhang, N. J. Cherrington, D. S. Sitar, and W. H. Dantzler
Functional map of TEA transport activity in isolated rabbit renal proximal tubules
Am J Physiol Renal Physiol, September 1, 2004; 287(3): F442 - F451.
[Abstract] [Full Text] [PDF]

Home page
 Physiol. Rev.Home page
S. H. Wright and W. H. Dantzler
Molecular and Cellular Physiology of Renal Organic Cation and Anion Transport
Physiol Rev, July 1, 2004; 84(3): 987 - 1049.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online
Copyright © 2003 by the American Physiological Society.