β1 and β2 Adrenoceptor Ligand and mRNA Expression in Dilated Cardiomyopathy

抄録

β1 and β2 adrenoceptor ligand activity has been shown to be down-regulated in failing myocardium. It is the aim of this study to test the hypothesis that also mRNA levels are down-regulated in dilated cardiomyopathy. β1 and β2 adrenoceptor ligand activities and mRNA expressions were analyzed in left ventricular biopsies from six organ donor hearts, in papillary muscles from seven patients operated on for mitral regurgitation, and in six explanted hearts as the result of dilated cardiomyophathy. mRNA levels were determined by solution hybridization. β1 ligand activity was decreased in the cases of mitral regurgitation (p<0.01) and dilated cardiomyopathy (p<0.001). β2 ligand activity did not differ between the three groups. mRNA expression was depressed in mitral regurgitation regarding both β1 (p<0.001) and β2 (p<0.01), while no differences were observed in dilated cardiomyopathy as compared to the donor hearts. The regulation of β1 and β2 adrenoceptor ligand activity and mRNA expression appears to follow a specific pattern in dilated cardiomyopathy. The specific down-regulation of β1 ligand activity seems to occur at a posttranslational level.