Inhibition of smooth muscle tension by cyclic AMP-dependent protein kinase

Nature. 1981 Jul 16;292(5820):253-5. doi: 10.1038/292253a0.


beta-Adrenergic relaxation of smooth muscle by catecholamines has been associated with elevated levels of cyclic AMP. The question arises whether subsequent activation of cyclic AMP-dependent protein kinase has a role in the regulation of smooth muscle contraction. There is substantial evidence that a Ca2+-activated myosin light chain kinase/phosphatase system regulates smooth muscle contraction, and Adelstein et al. have shown that the catalytic subunit of cyclic AMP-dependent protein kinase plays a part in this regulation, by phosphorylation of the high molecular weight subunit of the light chain kinase, which results in a decrease in the activity of the kinase. Here we have shown for the first time that the catalytic subunit of the protein kinase inhibits Ca2+-activated tension in skinned smooth muscle fiber preparations.

MeSH terms

  • Animals
  • Calcium / pharmacology*
  • Calmodulin / pharmacology
  • Chickens
  • Cyclic AMP / physiology
  • Gizzard, Avian / metabolism
  • Muscle Contraction / drug effects*
  • Muscle, Smooth / physiology*
  • Myosins / metabolism
  • Phosphorylation
  • Protein Kinase Inhibitors
  • Protein Kinases / physiology*


  • Calmodulin
  • Protein Kinase Inhibitors
  • Cyclic AMP
  • Protein Kinases
  • Myosins
  • Calcium