title: Identification of PDE isozymes in human pulmonary artery and effect of selective PDE inhibitors.
abstract: The effects of the nonselective phosphodiesterase (PDE) inhibitor 3-isobutyl-1-methylxanthine (IBMX) and the selective PDE inhibitors motapizone (type III), rolipram (type IV), zardaverine (type III/IV), and zaprinast (type V and I) on prostaglandin F2 alpha (PFG2 alpha)-induced tone in human pulmonary arteries was investigated. Relaxation was achieved by IBMX [concentration eliciting 50% of maximum response (EC50): 11.3 microM, n = 10], motapizone (EC50:3.0 microM, n = 7), zardaverine (EC50: 3.2 microM, n = 9), and zaprinast (EC50: 31.8 microM, n = 6), whereas rolipram was almost ineffective. The combination of motapizone and zaprinast (10 microM) was the most effective relaxant with supra-additive relaxation and a motapizone EC50 of 575 nM. Biochemical studies revealed the presence of the PDE isozymes I, III, IV and V in the cytosolic and particulate phases of arterial homogenates; PDE II was not detectable. Partial inhibition of adenosine 3',5'-cyclic monophosphate (cAMP)-hydrolyzing PDE activity was achieved with rolipram (26 +/- 2.2%) or motapizone (60 +/- 5.4%), whereas there was almost complete inhibition of total PDE activity with zardaverine (81 +/- 2.0%) or the combination of motapizone and rolipram (82 +/- 2.3%). Inhibition of guanosine 3',5'-cyclic monophosphate (cGMP)-hydrolyzing PDE activity was achieved with zaprinast (62 +/- 2.6%) and motapizone (13 +/- 2.3%), indicating the cGMP-hydrolyzing activity of PDE III. We conclude that four out of the five recognized PDE isozyme families are present in human pulmonary artery. PGF2 alpha-induced tone in this tissue is effectively relaxed through PDE inhibitors with selectivity for type III, III/IV, and type V PDE.
authors.affiliation: Krankenhaus Grosshansdorf, Zentrum für Pneumologie und Thoraxchirurgie, Landesversicherungsanstalt Freie und Hansestadt Hamburg, Grosshansdorf, Germany.
authors.forename: K F
authors.initials: KF
authors.lastname: Rabe
authors.forename: H
authors.initials: H
authors.lastname: Tenor
authors.forename: G
authors.initials: G
authors.lastname: Dent
authors.forename: C
authors.initials: C
authors.lastname: Schudt
authors.forename: M
authors.initials: M
authors.lastname: Nakashima
authors.forename: H
authors.initials: H
authors.lastname: Magnussen
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D003600:Cytosol / Q000201:enzymology; D015237:Dinoprost / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism; D007700:Kinetics; D008175:Lung Neoplasms / Q000201:enzymology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects; D009129:Muscle Tonus / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D009599:Nitroprusside / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D010727:Phosphoric Diester Hydrolases / Q000032:analysis / Q000378:metabolism*; D011651:Pulmonary Artery / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D011688:Purinones / Q000494:pharmacology; D011724:Pyridazines / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology; D020889:Rolipram
chemical_list: D000959:Antihypertensive Agents; D007527:Isoenzymes; D010726:Phosphodiesterase Inhibitors; D011688:Purinones; D011724:Pyridazines; D011760:Pyrrolidinones; D009599:Nitroprusside; D005576:Colforsin; D002217:Carbachol; D015237:Dinoprost; C051270:motapizone; D010727:Phosphoric Diester Hydrolases; C011145:zaprinast; D020889:Rolipram; D015056:1-Methyl-3-isobutylxanthine; C066436:zardaverine