| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Institut National de la Santé et de la Recherche Médicale U.426, Institut Fédératif de Recherche 02, Faculté de Médecine Xavier Bichat, Université Paris 7, 75018 Paris, France
We investigated the properties of K+ channels in the basolateral membrane of the cortical thick ascending limb (CTAL) using the patch-clamp technique. Approximately 34% of cell-attached patches contained an inwardly rectifying K+ channel (K+-to-Na+ permeability ratio ~22), having an inward conductance (Gin) of 44 pS and an outward conductance (Gout) of ~10 pS (Gin/Gout ~ 4). Channel activity (NPo) increased with depolarization. When the cytosolic sides of inside-out patches were exposed to an Mg2+-free medium, the channel had a Gin of 50 pS and was weakly inwardly rectifying (Gin/Gout ~ 1). Cytosolic Mg2+ reduced Gout, yielding a Gin/Gout of 3.8 at 1.3 mM Mg2+. Internal Na+ also yielded a Gin/Gout of 1.6 at 20 mM Na+. Spermine reduced NPo on inside-out membrane patches. Sensitivity to spermine at depolarizing voltages [half-maximal inhibitory concentration (Ki) = 0.2 µM] was much greater than at hyperpolarizing voltages (Ki = 26 µM). Half-inactivation by 0.5 µM spermine occurred at a clamp potential of 43 mV, with an effective valence of 1.25. A sigmoid relationship between bath pH and NPo of inside-out membrane patches was observed, with a pK of 7.6 and a Hill coefficient of 1.8. Intracellular acidification also reduced the NPo of cell-attached patches. This channel is probably a major component of K+ conductance in the CTAL basolateral membrane.
thick ascending limb of Henle's loop; basolateral membrane; potassium channel; patch clamp; mouse
This article has been cited by other articles:
|
|
 |
|
  S. Lachheb, F. Cluzeaud, M. Bens, M. Genete, H. Hibino, S. Lourdel, Y. Kurachi, A. Vandewalle, J. Teulon, and M. Paulais Kir4.1/Kir5.1 channel forms the major K+ channel in the basolateral membrane of mouse renal collecting duct principal cells Am J Physiol Renal Physiol, June 1, 2008; 294(6): F1398 - F1407. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Gu, J. Wang, Y. Zhang, W. Li, Y. Xu, H. Shan, W.-H. Wang, and B. Yang Adenosine stimulates the basolateral 50 pS K channels in the thick ascending limb of the rat kidney Am J Physiol Renal Physiol, July 1, 2007; 293(1): F299 - F305. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Nissant, M. Paulais, S. Lachheb, S. Lourdel, and J. Teulon Similar chloride channels in the connecting tubule and cortical collecting duct of the mouse kidney Am J Physiol Renal Physiol, June 1, 2006; 290(6): F1421 - F1429. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Paulais, S. Lachheb, and J. Teulon A Na+- and Cl--activated K+ Channel in the Thick Ascending Limb of Mouse Kidney J. Gen. Physiol., January 30, 2006; 127(2): 205 - 215. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. C. Hebert, G. Desir, G. Giebisch, and W. Wang Molecular Diversity and Regulation of Renal Potassium Channels Physiol Rev, January 1, 2005; 85(1): 319 - 371. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Wang The Effects of the Potassium Channel Opener Minoxidil on Renal Electrolytes Transport in the Loop of Henle J. Pharmacol. Exp. Ther., February 1, 2003; 304(2): 833 - 840. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R.-M. Gu and W.-H. Wang Arachidonic acid inhibits K channels in basolateral membrane of the thick ascending limb Am J Physiol Renal Physiol, September 1, 2002; 283(3): F407 - F414. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
