title: Inhibition of a high affinity cyclic AMP phosphodiesterase and relaxation of canine tracheal smooth muscle.
abstract: The cyclic nucleotide phosphodiesterase (PDE) activity of canine tracheal smooth muscle (CTS,) was examined. Column chromatography of soluble CTSM-PDE revealed five peaks of activity. One of these peaks (V) was examined further in this study and showed a high affinity for adenosine 3',5'-cyclic monophosphate (Km = 0.63 microM). Seven pharmacological PDE inhibitors were tested for their abilities to inhibit the peak V enzyme and also for their abilities to cause mechanical relaxation of CTSM strips in isolated tissue baths. A strong correlation (P greater than 0.001) between peak V PDE inhibition (-log Ki) and airway muscle relaxation (-log ED50) was found.
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors*; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004285:Dogs; D004974:Etazolate / Q000494:pharmacology; D005260:Female; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects*; D009130:Muscle, Smooth / Q000201:enzymology / Q000502:physiology*; D013806:Theophylline / Q000494:pharmacology; D014132:Trachea / Q000502:physiology; D014970:Xanthines / Q000494:pharmacology
chemical_list: D014970:Xanthines; C008514:methylxanthine; D002110:Caffeine; D013806:Theophylline; D000242:Cyclic AMP; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D004974:Etazolate