Cross-talk Between Adenosine A1Receptor And Kappa-opioid Receptor(k-OR) Activation On Isoproterenol-induced Cardiomyocyte Hypertrophy

ObjectiveThe purposes of this study were to observe the cross-talk and mechanismbetween adenosine A1receptor and kappa-opioid receptor(κ-OR) activation onIsoproterenol-induced cardiomyocyte hypertrophy in vitro cultured myocardialcells from neonatal rats.Methods1.To induce myocardial hypertrophy by using10μmol/L Iso in culturedmyocardial cells of neonatal rats. To observe the effects of1μmol/LR-PIA,1μmol/L U50488H,0.1μmol/L CPDPX and1μmol/L NOR-BNI onIso-induced myocardial hypertrophy.2.The protein content was assayed by the method of Lowry. Thecardiomyocytes volume was measured by computer photograph analysissystem. The expression of mRNA of atrial natriuretic peptide（ANP）wasdetermined by RT-PCR.The relative expression of CaN was determined byWestern blotting.[Ca2+]iwas measured by confocal microscope using Fluo-3/AMas flouresecent indicator.The cardiomyocytes morphology was observed byinverted phase contrast microscope. Results1.10μmol/L Iso can induced cardiomyocyte hypertrophy,1μmol/LR-PIA canobviously inhibit Iso-induced increase of the protein content,cardiomyocytesvolume and expression of mRNA of ANP;the inhibitory action can be opposedby1μmol/L nor-binaltorphimine （NOR-BNI）（antagonist of kappa-opioidreceptor）or0.1μmol/L CPDPX（antagonist of adenosine A1receptor）.2.10μmol/L Iso can induced cardiomyocyte hypertrophy,1μmol/LU50488Hcan obviously inhibit Iso-induced increase of the protein content,cardiomyocytesvolume and expression of mRNA of ANP;the inhibitory action can be opposedby0.1μmol/L CPDPX（antagonist of adenosine A1receptor）or1μmol/Lnor-binaltorphimine（NOR-BNI）（antagonist of kappa-opioid receptor）.Conclusion1.Adenosine can inhibit cardiomyocyte hypertrophy induced by Iso throughactivating adenosine A1receptor；opioid peptides can inhibit cardiomyocytehypertrophy induced by Iso through activating kappa-opioid receptor.2.The adenosine and opioid peptides have the cross-talk inhibition oncardiomyocyte hypertrophy induced by Isoproterenol.