Additional similarity of cardiac cAMP-activated Cl- channels to CFTR Cl- channels.
Isoproterenol, forskolin, or cAMP activated a time-independent Cl- current (ICl.cAMP), which is known to be activated by A-kinase-mediated phosphorylation, in guinea pig ventricular myocytes. External glibenclamide inhibited ICl.cAMP in a concentration-dependent manner with IC50 of around 30 microM. Thus, it is concluded that glibenclamide inhibits cardiac cAMP-activated Cl- channels and that the Cl- channel is, in this respect, similar to epithelial CFTR Cl- channel. Northern analysis actually indicated that CFTR messenger RNA is expressed in the guinea pig ventricle.
Tominaga
M
M
Department of Cellular and Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
Horie
M
M
Okada
Y
Y
D000818:Animals; D015152:Blotting, Northern; D018118:Chloride Channels / Q000502:physiology*; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology*; D003550:Cystic Fibrosis; D005905:Glyburide / Q000494:pharmacology; D006168:Guinea Pigs; D006321:Heart / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics
D018118:Chloride Channels; D012333:RNA, Messenger; D005576:Colforsin; D000242:Cyclic AMP; D005905:Glyburide