Elena Isaeva1,2, Ruslan Bohovyk1,2,3, Mykhailo Fedoriuk1,2, Alexey Shalygin1,4, Christine A Klemens1,3,5, Adrian Zietara1,3, Vladislav Levchenko1,3, Jerod S Denton6, Alexander Staruschenko1,3,5,7, Oleg Palygin1,8. 1. Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA. 2. Department of Cellular Membranology, Bogomoletz Institute of Physiology, Kyiv, Ukraine. 3. Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, Florida, USA. 4. Department of Molecular and Cellular Physiology, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg, Russia. 5. Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA. 6. Department of Anesthesiology and Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. 7. Clement J. Zablocki VA Medical Center, Milwaukee, Wisconsin, USA. 8. Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, South Carolina, USA.
Abstract
BACKGROUND AND PURPOSE: Inwardly rectifying K+ (Kir ) channels located on the basolateral membrane of epithelial cells of the distal nephron play a crucial role in K+ handling and BP control, making these channels an attractive target for the treatment of hypertension. The purpose of the present study was to determine how the inhibition of basolateral Kir 4.1/Kir 5.1 heteromeric K+ channel affects epithelial sodium channel (ENaC)-mediated Na+ transport in the principal cells of cortical collecting duct (CCD). EXPERIMENTAL APPROACH: The effect of fluoxetine, amitriptyline and recently developed Kir inhibitor, VU0134992, on the activity of Kir 4.1, Kir 4.1/Kir 5.1 and ENaC were tested using electrophysiological approaches in CHO cells transfected with respective channel subunits, cultured polarized epithelial mCCDcl1 cells and freshly isolated rat and human CCD tubules. To test the effect of pharmacological Kir 4.1/Kir 5.1 inhibition on electrolyte homeostasis in vivo and corresponding changes in distal tubule transport, Dahl salt-sensitive rats were injected with amitriptyline (15 mg·kg-1 ·day-1 ) for 3 days. KEY RESULTS: We found that inhibition of Kir 4.1/Kir 5.1, but not the Kir 4.1 channel, depolarizes the cell membrane, induces the elevation of intracellular Ca2+ concentration and suppresses ENaC activity. Furthermore, we demonstrate that amitriptyline administration leads to a significant drop in plasma K+ level, triggering sodium excretion and diuresis. CONCLUSION AND IMPLICATIONS: The present data uncover a specific role of the Kir 4.1/Kir 5.1 channel in the modulation of ENaC activity and emphasize the potential for using Kir 4.1/Kir 5.1 inhibitors to regulate electrolyte homeostasis and BP.
BACKGROUND AND PURPOSE: Inwardly rectifying K+ (Kir ) channels located on the basolateral membrane of epithelial cells of the distal nephron play a crucial role in K+ handling and BP control, making these channels an attractive target for the treatment of hypertension. The purpose of the present study was to determine how the inhibition of basolateral Kir 4.1/Kir 5.1 heteromeric K+ channel affects epithelial sodium channel (ENaC)-mediated Na+ transport in the principal cells of cortical collecting duct (CCD). EXPERIMENTAL APPROACH: The effect of fluoxetine, amitriptyline and recently developed Kir inhibitor, VU0134992, on the activity of Kir 4.1, Kir 4.1/Kir 5.1 and ENaC were tested using electrophysiological approaches in CHO cells transfected with respective channel subunits, cultured polarized epithelial mCCDcl1 cells and freshly isolated rat and human CCD tubules. To test the effect of pharmacological Kir 4.1/Kir 5.1 inhibition on electrolyte homeostasis in vivo and corresponding changes in distal tubule transport, Dahl salt-sensitive rats were injected with amitriptyline (15 mg·kg-1 ·day-1 ) for 3 days. KEY RESULTS: We found that inhibition of Kir 4.1/Kir 5.1, but not the Kir 4.1 channel, depolarizes the cell membrane, induces the elevation of intracellular Ca2+ concentration and suppresses ENaC activity. Furthermore, we demonstrate that amitriptyline administration leads to a significant drop in plasma K+ level, triggering sodium excretion and diuresis. CONCLUSION AND IMPLICATIONS: The present data uncover a specific role of the Kir 4.1/Kir 5.1 channel in the modulation of ENaC activity and emphasize the potential for using Kir 4.1/Kir 5.1 inhibitors to regulate electrolyte homeostasis and BP.
Authors: Detlef Bockenhauer; Sally Feather; Horia C Stanescu; Sascha Bandulik; Anselm A Zdebik; Markus Reichold; Jonathan Tobin; Evelyn Lieberer; Christina Sterner; Guida Landoure; Ruchi Arora; Tony Sirimanna; Dorothy Thompson; J Helen Cross; William van't Hoff; Omar Al Masri; Kjell Tullus; Stella Yeung; Yair Anikster; Enriko Klootwijk; Mike Hubank; Michael J Dillon; Dirk Heitzmann; Mauricio Arcos-Burgos; Mark A Knepper; Angus Dobbie; William A Gahl; Richard Warth; Eamonn Sheridan; Robert Kleta Journal: N Engl J Med Date: 2009-05-07 Impact factor: 91.245
Authors: Oleg Palygin; Vladislav Levchenko; Daria V Ilatovskaya; Tengis S Pavlov; Oleh M Pochynyuk; Howard J Jacob; Aron M Geurts; Matthew R Hodges; Alexander Staruschenko Journal: JCI Insight Date: 2017-09-21
Authors: Daria Golosova; Oleg Palygin; Ruslan Bohovyk; Christine A Klemens; Vladislav Levchenko; Denisha R Spires; Elena Isaeva; Ashraf El-Meanawy; Alexander Staruschenko Journal: Life Sci Alliance Date: 2020-10-12