caa a22 4500 477120296 CHVBK 20180405111635.0 cr unu---uuuuu 170330e19960401xx s 000 0 eng 10.1007/BF00227898 doi (NATIONALLICENCE)springer-10.1007/BF00227898 β-Adrenoceptor mediated signal transduction in congestive heart failure in cardiomyopathic (UMX7.1) hamsters [Elektronische Daten] [Deepak Kaura, Nobuakira Takeda, Rajat Sethi, Xi Wang, Makoto Nagano, Naranjan Dhalla] In view of the lack of information regarding the status of β-adrenoceptor mediated signal transduction mechanisms at severe stages of congestive heart failure, the status of β-adrenoceptors, G-proteins and adenylyl cyclase activities was examined in 2202-275 day old cardiomyopathic hamster hearts. Although no changes in the Kd values for β1- and β2-adrenoceptors were seen, the number of β1-adrenoceptors, unlike that of R2-adrenoceptors, was markedly decreased in cardiac membranes from failing hearts. The activation of adenylyl cyclase in the failing hearts by different concentrations of isoproterenol was also attenuated in comparison to the control preparations. The basal adenylyl cyclase activity in cardiac membranes from the failing hearts was not altered; however, the stimulated enzyme activities, when measured in the presence of forskolin, NaF or Gpp(NH)p were depressed significantly. The functional activity of Gs-proteins (measured by cholera toxin stimulation of adenylyl cyclase) was depressed whereas that of Gi-proteins (measured by pertussis toxin stimulation of adenylyl cyclase) was increased in the failing hearts. Not only were the Gs- and Gi-protein contents (measured by immunoblotting) increased, the bioactivities of these proteins as determined by ADP-ribosylations in the presence of cholera toxin and pertussis toxin, respectively, were also higher in failing hearts in comparison to the control values. Northern blot analysis revealed that the signals for Gs- and Gi-protein mRNAs were augmented at this stage of heart failure. These results indicate that the loss of adrenergic support at severe stages of congestive heart failure in cardiomyopathic hamsters may involve a reduction in the number of β1-adrenoceptors, and an increase in Gi-protein contents as well as bioactivities in addition to an uncoupling of Gs-proteins from the catalytic site of adenylyl cyclase in cardiac membrane. Kluwer Academic Publishers, 1996 cardiac β-adrenoceptors nationallicence adenylyl cyclase in heart nationallicence myocardial G-proteins nationallicence signal transduction mechanisms nationallicence congestive heart failure nationallicence cardiomyopathic hamsters nationallicence Kaura Deepak St. Boniface General Hospital Research Centre, Division of Cardiovascular Sciences, 351 Tache Avenue, R2H 2A6, Winnipeg, Manitoba, Canada aut Takeda Nobuakira Department of Internal Medicine, Aoto Hospital, Jikei University, Tokyo, Japan aut Sethi Rajat St. Boniface General Hospital Research Centre, Division of Cardiovascular Sciences, 351 Tache Avenue, R2H 2A6, Winnipeg, Manitoba, Canada aut Wang Xi St. Boniface General Hospital Research Centre, Division of Cardiovascular Sciences, 351 Tache Avenue, R2H 2A6, Winnipeg, Manitoba, Canada aut Nagano Makoto Department of Internal Medicine, Aoto Hospital, Jikei University, Tokyo, Japan aut Dhalla Naranjan St. Boniface General Hospital Research Centre, Division of Cardiovascular Sciences, 351 Tache Avenue, R2H 2A6, Winnipeg, Manitoba, Canada aut Molecular and Cellular Biochemistry Kluwer Academic Publishers 157/1-2(1996-04-01), 191-196 0300-8177 157:1-2<191 1996 157 11010 https://doi.org/10.1007/BF00227898 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00227898 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kaura Deepak St. Boniface General Hospital Research Centre, Division of Cardiovascular Sciences, 351 Tache Avenue, R2H 2A6, Winnipeg, Manitoba, Canada aut NATIONALLICENCE 700 1- Takeda Nobuakira Department of Internal Medicine, Aoto Hospital, Jikei University, Tokyo, Japan aut NATIONALLICENCE 700 1- Sethi Rajat St. Boniface General Hospital Research Centre, Division of Cardiovascular Sciences, 351 Tache Avenue, R2H 2A6, Winnipeg, Manitoba, Canada aut NATIONALLICENCE 700 1- Wang Xi St. Boniface General Hospital Research Centre, Division of Cardiovascular Sciences, 351 Tache Avenue, R2H 2A6, Winnipeg, Manitoba, Canada aut NATIONALLICENCE 700 1- Nagano Makoto Department of Internal Medicine, Aoto Hospital, Jikei University, Tokyo, Japan aut NATIONALLICENCE 700 1- Dhalla Naranjan St. Boniface General Hospital Research Centre, Division of Cardiovascular Sciences, 351 Tache Avenue, R2H 2A6, Winnipeg, Manitoba, Canada aut NATIONALLICENCE 773 0- Molecular and Cellular Biochemistry Kluwer Academic Publishers 157/1-2(1996-04-01), 191-196 0300-8177 157:1-2<191 1996 157 11010 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer