Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
XB-ART-40192
J Physiol 2009 Jun 01;587Pt 11:2663-76. doi: 10.1113/jphysiol.2009.170324.
Show Gene links Show Anatomy links

Regulation of epithelial sodium channels by cGMP/PKGII.

Nie HG, Chen L, Han DY, Li J, Song WF, Wei SP, Fang XH, Gu X, Matalon S, Ji HL.


???displayArticle.abstract???
Airway and alveolar fluid clearance is mainly governed by vectorial salt movement via apically located rate-limiting Na(+) channels (ENaC) and basolateral Na(+)/K(+)-ATPases. ENaC is regulated by a spectrum of protein kinases, i.e. protein kinase A (PKA), C (PKC), and G (PKG). However, the molecular mechanisms for the regulation of ENaC by cGMP/PKG remain to be elucidated. In the present study, we studied the pharmacological responses of native epithelial Na(+) channels in human Clara cells and human alphabetagammadelta ENaCs expressed in oocytes to cGMP. 8-pCPT-cGMP increased amiloride-sensitive short-circuit current (I(sc)) across H441 monolayers and heterologously expressed alphabetagammadelta ENaC activity in a dose-dependent manner. Similarly, 8-pCPT-cGMP (a PKGII activator) but not 8-Br-cGMP (a PKGI activator) increased amiloride-sensitive whole cell currents in H441 cells in the presence of CFTRinh-172 and diltiazem. In all cases, the cGMP-activated Na(+) channel activity was inhibited by Rp-8-pCPT-cGMP, a specific PKGII inhibitor. This was substantiated by the evidence that PKGII was the sole isoform expressed in H441 cells at the protein level. Importantly, intratracheal instillation of 8-pCPT-cGMP in BALB/c mice increased amiloride-sensitive alveolar fluid clearance by approximately 30%, consistent with the in vitro results. We therefore conclude that PKGII is an activator of lung epithelial Na(+) channels, which may expedite the resolution of oedematous fluid in alveolar sacs.

???displayArticle.pubmedLink??? 19359370
???displayArticle.pmcLink??? PMC2714029
???displayArticle.link??? J Physiol
???displayArticle.grants??? [+]

Species referenced: Xenopus
Genes referenced: prkg1 sacs uqcc6

References [+] :
Albert, AICAR decreases the activity of two distinct amiloride-sensitive Na+-permeable channels in H441 human lung epithelial cell monolayers. 2008, Pubmed