Effects of adenosine receptor and muscarinic cholinergic receptor agonists on cardiac protein phosphorylation. Influence of pertussis toxin.
In isolated 32P-labeled guinea pig ventricular cardiomyocytes phospholamban (PLB), myosin light chain 2 and the inhibitory subunit of troponin (Tnl) were identified by antibodies. In isolated 32P-labeled guinea pig ventricular cardiomyocytes isoproterenol (0.1 mumol/l) increased phosphorylation of PLB and of the inhibitory subunit of Tnl to 159 and 119% of control, respectively, without effect on the phosphorylation state of myosin light chain 2. Additionally applied carbachol or (-)-N6-phenylisopropyladenosine reduced phosphorylation of PLB and Tnl without reducing cyclic AMP content. After pretreatment of guinea pigs with pertussis toxin (18 micrograms/100 g b.wt.), carbachol or (-)-N6-phenylisopropyladenosine failed to reduce isoproterenol-stimulated phosphorylation of both PLB and Tnl. It is concluded that the reductions by carbachol and (-)-N6-phenylisopropyladenosine of isoproterenol-stimulated PLB phosphorylation and Tnl phosphorylation are pertussis toxin-sensitive.
Abteilung Allgemeine Pharmakologie, Universitäts-Krankenhaus Eppendorf, Hamburg, Federal Republic of Germany.
J
J
Neumann
P
P
Bokník
G S
GS
Bodor
L R
LR
Jones
W
W
Schmitz
H
H
Scholz
D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009218:Myosins / Q000378:metabolism*; D037342:Pertussis Toxin; D010660:Phenylisopropyladenosine / Q000494:pharmacology; D010766:Phosphorylation; D011976:Receptors, Muscarinic / Q000502:physiology*; D018047:Receptors, Purinergic P1 / Q000502:physiology*; D014336:Troponin / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*; D000099211:Phospholamban
D002135:Calcium-Binding Proteins; D002217:Carbachol; D017868:Cyclic AMP-Dependent Protein Kinases; D009218:Myosins; D037342:Pertussis Toxin; D010660:Phenylisopropyladenosine; D011976:Receptors, Muscarinic; D018047:Receptors, Purinergic P1; D014336:Troponin; D010566:Virulence Factors, Bordetella; D000099211:Phospholamban