title: Functional interaction of a beta-adrenergic agonist and cyclic GMP phosphodiesterase inhibitor in control and hypertrophic cardiomyocytes.
abstract: This study tested the hypothesis that the positive inotropic effect of beta-adrenoceptor stimulation would be inhibited by increases in cyclic GMP in control cardiomyocytes and that this response would be modified in hypertrophic cardiomyocytes. Cell functional data as well as GMP and cyclic AMP data were collected from 7 control and 7 1K1C (one-kidney-one-clip) renal hypertensive hypertrophic rabbits. Using isolated control and IKIC ventricular myocytes, data were obtained at baseline and after treatment with the beta-adrenoceptor agonist isoproterenol (10(-8, -6) mol/l) or the cyclic GMP-phosphodiesterase inhibitor zaprinast (10(-5) mol/l) followed by isoproterenol (10(-8, -6) mol/l). We found that in control rabbits, isoproterenol (10(-6) mol/l) increased percent shortening (4.8 +/- 0.2 to 6.4 +/- 0.3%) and cyclic AMP (2.3 +/- 0.3 to 5.0 +/- 0.7 pmol/10(5) cells). Zaprinast 10(-5) mol/l increased cyclic GMP (150 +/- 20 to 209 +/- 14 fmol/10(5) cells) and decreased percent shortening (6.2 +/- 0.4 to 5.2 +/- 0.3). Zaprinast 10(-5) mol/l prevented the functional response to isoproterenol in control (5.2 +/- 0.3 to 4.7 +/- 0.3), without changing cyclic AMP levels. In 1K1C rabbits, isoproterenol (10(-6) mol/l) increased cyclic AMP (4.9 +/- 0.8 to 7.6 +/- 1.4 pmol/10(5) cells) without changing function. Zaprinast 10(-5) mol/l increased cyclic GMP (182 +/- 23 to 233 +/- 24 fmol/10(5) cells) and decreased percent shortening (6.6 +/- 0.9 to 4.7 +/- 0.5), but did not alter the lack of effect of isoproterenol in 1K1C. In control cardiomyocytes, cyclic GMP blunted the isoproterenol contraction response without changing cyclic AMP levels, but isoproterenol's functional effect was not seen in 1K1C cardiomyocytes.
authors.affiliation: Heart and Brain Circulation Laboratory, Department of Physiology and Biophysics, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, N.J. 08854, USA.
authors.forename: Shengjun
authors.initials: S
authors.lastname: Zhang
authors.forename: Roberto
authors.initials: R
authors.lastname: Rodriguez
authors.forename: Peter M
authors.initials: PM
authors.lastname: Scholz
authors.forename: Harvey R
authors.initials: HR
authors.lastname: Weiss
mesh_terms: D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000037:antagonists & inhibitors*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D006332:Cardiomegaly / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology*; D049108:Cell Enlargement; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006977:Hypertension, Renal / Q000503:physiopathology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D009200:Myocardial Contraction; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D011688:Purinones / Q000494:pharmacology*; D011817:Rabbits
chemical_list: D000318:Adrenergic beta-Agonists; D011688:Purinones; D000242:Cyclic AMP; D015106:3',5'-Cyclic-GMP Phosphodiesterases; C011145:zaprinast; D006152:Cyclic GMP; D007545:Isoproterenol