HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 289/4/F922    most recent 00057.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (15) Citing Articles via Google Scholar Google Scholar Articles by Najjar, F. Articles by Satlin, L. M. Search for Related Content PubMed PubMed Citation Articles by Najjar, F. Articles by Satlin, L. M.

Dietary K⁺ regulates apical membrane expression of maxi-K channels in rabbit cortical collecting duct

¹Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; and ²Division of Pediatric Nephrology, Department of Pediatrics, Mount Sinai School of Medicine, New York, New York

Submitted 10 February 2005 ; accepted in final form 16 May 2005

The cortical collecting duct (CCD) is a final site for regulation of K⁺ homeostasis. CCD K⁺ secretion is determined by the electrochemical gradient and apical permeability to K⁺. Conducting secretory K⁺ (SK/ROMK) and maxi-K channels are present in the apical membrane of the CCD, the former in principal cells and the latter in both principal and intercalated cells. Whereas SK channels mediate baseline K⁺ secretion, maxi-K channels appear to participate in flow-stimulated K⁺ secretion. Chronic dietary K⁺ loading enhances the CCD K⁺ secretory capacity due, in part, to an increase in SK channel density (Palmer et al., J Gen Physiol 104: 693–710, 1994). Long-term exposure of Ambystoma tigrinum to elevated K⁺ increases renal K⁺ excretion due to an increase in apical maxi-K channel density in their CDs (Stoner and Viggiano, J Membr Biol 162: 107–116, 1998). The purpose of the present study was to test whether K⁺ adaptation in the mammalian CCD is associated with upregulation of maxi-K channel expression. New Zealand White rabbits were fed a low (LK), control (CK), or high (HK) K⁺ diet for 10–14 days. Real-time PCR quantitation of message encoding maxi-K - and _2–4-subunits in single CCDs from HK animals was greater than that detected in CK and LK animals (P < 0.05); ₁-subunit was not detected in any CCD sample but was present in whole kidney. Indirect immunofluorescence microscopy revealed a predominantly intracellular distribution of -subunits in LK kidneys. In contrast, robust apical labeling was detected primarily in -intercalated cells in HK kidneys. In summary, K⁺ adaptation is associated with an increase in steady-state abundance of maxi-K channel subunit-specific mRNAs and immunodetectable apical -subunit, the latter observation consistent with redistribution from an intracellular pool to the plasma membrane.

potassium adaptation; intercalated cell; principal cell; in vitro microperfusion; H⁺-K⁺-ATPase

This article has been cited by other articles:

				G. Estilo, W. Liu, N. Pastor-Soler, P. Mitchell, M. D. Carattino, T. R. Kleyman, and L. M. Satlin Effect of aldosterone on BK channel expression in mammalian cortical collecting duct Am J Physiol Renal Physiol, September 1, 2008; 295(3): F780 - F788. [Abstract] [Full Text] [PDF]

				M. V. Sorensen, J. E. Matos, M. Sausbier, U. Sausbier, P. Ruth, H. A. Praetorius, and J. Leipziger Aldosterone increases KCa1.1 (BK) channel-mediated colonic K+ secretion J. Physiol., September 1, 2008; 586(17): 4251 - 4264. [Abstract] [Full Text] [PDF]

				D. I. Levy, S. Wanderling, D. Biemesderfer, and S. A. N. Goldstein MiRP3 acts as an accessory subunit with the BK potassium channel Am J Physiol Renal Physiol, August 1, 2008; 295(2): F380 - F387. [Abstract] [Full Text] [PDF]

				R. M. Foutz, P. R. Grimm, and S. C. Sansom Insulin increases the activity of mesangial BK channels through MAPK signaling Am J Physiol Renal Physiol, June 1, 2008; 294(6): F1465 - F1472. [Abstract] [Full Text] [PDF]

				F. Lang, V. Vallon, M. Knipper, and P. Wangemann Functional significance of channels and transporters expressed in the inner ear and kidney Am J Physiol Cell Physiol, October 1, 2007; 293(4): C1187 - C1208. [Abstract] [Full Text] [PDF]

				W. Liu, T. Morimoto, C. Woda, T. R. Kleyman, and L. M. Satlin Ca2+ dependence of flow-stimulated K secretion in the mammalian cortical collecting duct Am J Physiol Renal Physiol, July 1, 2007; 293(1): F227 - F235. [Abstract] [Full Text] [PDF]

				P. R. Grimm, R. M. Foutz, R. Brenner, and S. C. Sansom Identification and localization of BK-beta subunits in the distal nephron of the mouse kidney Am J Physiol Renal Physiol, July 1, 2007; 293(1): F350 - F359. [Abstract] [Full Text] [PDF]

				M. D. Carattino, W. Liu, W. G. Hill, L. M. Satlin, and T. R. Kleyman Lack of a role of membrane-protein interactions in flow-dependent activation of ENaC Am J Physiol Renal Physiol, July 1, 2007; 293(1): F316 - F324. [Abstract] [Full Text] [PDF]

				L. G. Palmer and G. Frindt High-conductance K channels in intercalated cells of the rat distal nephron Am J Physiol Renal Physiol, March 1, 2007; 292(3): F966 - F973. [Abstract] [Full Text] [PDF]

				L. M. Satlin, M. D. Carattino, W. Liu, and T. R. Kleyman Regulation of cation transport in the distal nephron by mechanical forces Am J Physiol Renal Physiol, November 1, 2006; 291(5): F923 - F931. [Abstract] [Full Text] [PDF]

				J. L. Pluznick and S. C. Sansom BK channels in the kidney: role in K+ secretion and localization of molecular components Am J Physiol Renal Physiol, September 1, 2006; 291(3): F517 - F529. [Abstract] [Full Text] [PDF]