Deprecated: Implicit conversion from float 231.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 231.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 231.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 231.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 231.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 231.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 231.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 231.6 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 265.2 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 265.2 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 265.2 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 265.2 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534
Deprecated: Implicit conversion from float 265.2 to int loses precision in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 534 Am+J+Physiol+Renal+Physiol 2014 ; 307 (7): F833-43 Nephropedia Template TP
gab.com Text
Twit Text FOAVip
Twit Text #
English Wikipedia
Angiotensin II type 2 receptor regulates ROMK-like K+ channel activity in the renal cortical collecting duct during high dietary K+ adaptation #MMPMID25100281
Wei Y; Liao Y; Zavilowitz B; Ren J; Liu W; Chan P; Rohatgi R; Estilo G; Jackson EK; Wang WH; Satlin LM
Am J Physiol Renal Physiol 2014[Oct]; 307 (7): F833-43 PMID25100281show ga
The kidney adjusts K+ excretion to match intake in part by regulation of the activity of apical K+ secretory channels, including renal outer medullary K+ (ROMK)-like K+ channels, in the cortical collecting duct (CCD). ANG II inhibits ROMK channels via the ANG II type 1 receptor (AT1R) during dietary K+ restriction. Because AT1Rs and ANG II type 2 receptors (AT2Rs) generally function in an antagonistic manner, we sought to characterize the regulation of ROMK channels by the AT2R. Patch-clamp experiments revealed that ANG II increased ROMK channel activity in CCDs isolated from high-K+ (HK)-fed but not normal K+ (NK)-fed rats. This response was blocked by PD-123319, an AT2R antagonist, but not by losartan, an AT1R antagonist, and was mimicked by the AT2R agonist CGP-42112. Nitric oxide (NO) synthase is present in CCD cells that express ROMK channels. Blockade of NO synthase with N-nitro-l-arginine methyl ester and free NO with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt completely abolished ANG II-stimulated ROMK channel activity. NO enhances the synthesis of cGMP, which inhibits phosphodiesterases (PDEs) that normally degrade cAMP; cAMP increases ROMK channel activity. Pretreatment of CCDs with IBMX, a broad-spectrum PDE inhibitor, or cilostamide, a PDE3 inhibitor, abolished the stimulatory effect of ANG II on ROMK channels. Furthermore, PKA inhibitor peptide, but not an activator of the exchange protein directly activated by cAMP (Epac), also prevented the stimulatory effect of ANG II. We conclude that ANG II acts at the AT2R to stimulate ROMK channel activity in CCDs from HK-fed rats, a response opposite to that mediated by the AT1R in dietary K+-restricted animals, via a NO/cGMP pathway linked to a cAMP-PKA pathway.