8Br-cGMP mediates relaxation of tracheal smooth muscle through PKA

Biochem Biophys Res Commun. 2004 Feb 6;314(2):597-601. doi: 10.1016/j.bbrc.2003.12.136.


In this study, guinea pig tracheal smooth muscle pre-contracted with histamine was relaxed by the addition of 100microM 8Br-cGMP, a non-hydrolyzable and cell-permeable analog for cGMP. This effect was not sensitive to cGMP-dependent protein kinase (PKG) inhibitors, whereas it was partially blocked by cAMP-dependent protein kinase (PKA) inhibitors. The relaxation observed was also reverted up to 50+/-8.5% by iberiotoxin, a selective inhibitor of large conductance, calcium-activated potassium channels (BK(Ca)). Our results indicate that there exists a crosstalk mechanism between cAMP and cGMP signaling pathways which lead to relaxation of guinea pig tracheal smooth muscle and also that BK(Ca) channels are involved to a certain extent in this phenomenon.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Cyclic AMP-Dependent Protein Kinases / physiology*
  • Cyclic GMP / analogs & derivatives*
  • Cyclic GMP / metabolism
  • Cyclic GMP / physiology*
  • Enzyme Inhibitors / pharmacology
  • Guinea Pigs
  • Histamine / metabolism
  • Male
  • Myocytes, Smooth Muscle / drug effects
  • Myocytes, Smooth Muscle / enzymology*
  • Peptides / pharmacology
  • Signal Transduction
  • Toxins, Biological
  • Trachea / cytology*
  • Trachea / drug effects


  • Enzyme Inhibitors
  • Peptides
  • Toxins, Biological
  • 8-bromocyclic GMP
  • iberiotoxin
  • Histamine
  • Cyclic AMP-Dependent Protein Kinases
  • Cyclic GMP