The role of phosphodiesterase in mediating the effect of protein kinase C on cyclic AMP accumulation upon kappa-opioid receptor stimulation in the rat heart.
This study determined whether phosphodiesterase (PDE) was activated by protein kinase C (PKC) upon kappa-receptor stimulation, and if so, to identify the isozyme. We first studied the effects of trans-(+/-)-3,4-dichloro-N-methyl-N-(2-[1-pyrrolidinyl] cyclohexyl) benzeneacetamide methanesulphonate (U50,488H), a selective kappa-opioid receptor (OR) agonist, and phorbol-12-myristate-13-acetate (PMA), a PKC activator, on cAMP accumulation and PDE activity in rat ventricular myocytes when PKC and PDE were inhibited by respective inhibitors. Like PMA, U50,488H decreased the forskolin-stimulated cAMP accumulation and dose-dependently stimulated the PDE activity, which were antagonized by 10(-6) M chelerythrine and bisindolylmaleimide I, selective PKC antagonists. In addition, 3-isobutyl-1-methylxanthine, a PDE inhibitor, dose-dependently attenuated the inhibition on forskolin-stimulated cAMP accumulation and abolished the stimulation on PDE activity by U50,488H and PMA. The observations suggest that PKC may enhance cAMP degradation through activating PDE upon kappa-OR stimulation. To identify the isozyme(s) mediating the effect of PKC upon kappa-OR stimulation, selective inhibitors were used. We found that 10(-5) M Ro-20-1724, a selective cAMP-specific PDE (PDE-IV) inhibitor, abolished the inhibitory effects of U50,488H and PMA, whereas 8-methoxymethyl-3-isobutyl-1-methylxanthine, erythro-9-(2-hydroxy-3-nonyl) adenine, cilostamide, and zaprinast, selective inhibitors of Ca(2+)/calmodulin-dependent PDE (PDE-I), cGMP-stimulated PDE (PDE-II), cGMP-inhibited PDE (PDE-III), and cGMP-specific PDE (PDE-V), respectively, had no effect. Moreover, rolipram, another selective PDE-IV inhibitor, also dose-dependently attenuated the inhibition on forskolin-stimulated cAMP accumulation and stimulation on PDE activity by U50,488H and PMA. In conclusion, this study has provided evidence for the first time that PKC and PDE-IV mediate the action of kappa-OR.
Bian
J S
JS
Department of Physiology, Institute of Cardiovascular Science and Medicine, Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
Zhang
W M
WM
Pei
J M
JM
Wong
T M
TM
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer / Q000494:pharmacology; D000470:Alkaloids; D000818:Animals; D053119:Benzophenanthridines; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D008297:Male; D009206:Myocardium / Q000378:metabolism; D010617:Phenanthridines / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000502:physiology*; D011493:Protein Kinase C / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017473:Receptors, Opioid, kappa / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000470:Alkaloids; D053119:Benzophenanthridines; D010617:Phenanthridines; D010726:Phosphodiesterase Inhibitors; D017473:Receptors, Opioid, kappa; D005576:Colforsin; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000242:Cyclic AMP; C016299:chelerythrine; D011493:Protein Kinase C; D010727:Phosphoric Diester Hydrolases; D013755:Tetradecanoylphorbol Acetate; D015056:1-Methyl-3-isobutylxanthine