Beta-adrenoceptor stimulation attenuates the hypertrophic effect of alpha-adrenoceptor stimulation in adult rat ventricular cardiomyocytes
Matthias Schäfer, PhD*,
Klaus Pönicke, PhD ,
Ingrid Heinroth-Hoffmann, PhD,
Otto-Erich Brodde, PhD*,
Hans Michael Piper, MD, PhD* and
Klaus-Dieter Schlüter, PhD*
* Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany
Institut fur, Pharmakologie und Toxikologie, Martin-Luther-Universität Halle, Halle, Germany
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Figure 1 Incorporation of 3H-phenylalanine (Phe) of cardiomyocytes cultured for 20 h in the presence of norepinephrine (NOR) at concentrations indicated (open bars) and (A) in the presence of prazosin (0.1 µmol/liter; filled bars) or (B) propranolol (1 µmol/liter; filled bars). Data are expressed as percentages relative to the control values. Data are means ± SEM from n = 8 cultures. * = p < 0.05 vs. each other; ** = p < 0.01 vs. each other; n.d. = not determined.
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Figure 2 Incorporation of 3H-phenylalanine (Phe) of cardiomyocytes cultured for 20 h in the presence of norepinephrine (NOR, open bars) at concentrations indicated, in the presence of NOR and CPG 20712A (300 nmol/liter; filled bars) or in the presence of NOR and ICI 118,551 (55 nmol/liter; hatched bars). Data are expressed as percentages relative to the control values. Data are means ± SEM from n = 8 cultures. * = p < 0.05 vs. each other; ** = p < 0.01 vs. each other.
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Figure 3 Incorporation of 14C-phenylalanine (Phe) of cardiomyocytes cultured for 24 h in the presence of norepinephrine (NOR) at concentrations indicated (open bars) or NOR and atenolol (1 µmol/liter; filled bars). Data are expressed as percentages relative to the control values. Data are means ± SEM from n = 6 cultures. * = p < 0.05 vs. each other.
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Figure 4 Incorporation of 14C-phenylalanine (Phe) and protein mass (protein/DNA ratio) of cardiomyocytes cultured for 24 h in presence of phenylephrine (PE, 10 µmol/liter), norepinephrine (NOR, 1 µmol/liter), or NOR and atenolol (ATE, 1 µmol/liter). Data are expressed as percentages relative to the control values. Data are means ± SEM from n = 6 cultures. * = p < 0.05 vs. control; # = p < 0.05 vs. NOR. Open bars = PE; filled bars = NOR; hatched bars = ATE + NOR.
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Figure 5 Incorporation of 14C-uridine (Uri) and RNA mass (RNA/DNA ratio) of cardiomyocytes cultured in presence of phenylephrine (PE, 10 µmol/liter), norepinephrine (NOR, 1 µmol/liter), or NOR and atenolol (ATE, 1 µmol/liter). Cells were incubated with the agonists for 6 h in case of RNA synthesis and 24 h in case of RNA mass. Data are expressed as percentages relative to the control values. Data are means ± SEM from n = 6 cultures. * = p < 0.05 vs. C; # = p < 0.05 vs. NOR. Open bars = PE; filled bars = NOR; hatched bars = ATE + NOR.
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Figure 6 (A) Western blots indicating the translocation of protein kinase C (PKC) isoforms  and  into the particular fraction. Cells were incubated for 5 min (control, C), with norepinephrine (NOR, 1 µmol/liter) or norepinephrine and atenolol (NOR + Ate, 1 µmol/liter). (B) Incorporation of 14C-phenylalanine (Phe) of cardiomyocytes cultured for 24 h in presence of phenylephrine (PE, 10 µmol/liter), phorbol myristate acetate (PMA, 0.1 µmol/liter), or PE and PMA in co-presence of isoprenaline (1 µmol/liter) and ICI 118,551 (ICI, 0.1 µmol/liter) (ISO + ICI). Data are expressed as percentages relative to the control values. Data are means ± SEM from n = 6 cultures. * = p < 0.05 vs. each other.
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Figure 7 Incorporation of 14C-phenylalanine (Phe) of cardiomyocytes cultured for 24 h in presence of norepinephrine (NOR, 1 µmol/liter), phenylephrine (PE, 10 µmol/liter), or PE in co-presence of isoprenaline (1 µmol/liter) and ICI 118,551 (ICI, 0.1 µmol/liter) (ISO + ICI). Where indicated Rp-cAMPS (RpcAMPS, 10 µmol/liter) or dibutyryl-cAMP (dbcAMP, 1 mmol/liter) was added. Data are expressed as percentages relative to the control values. Data are means ± SEM from n = 6 cultures. * = p < 0.05 vs. each other.
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