Role of guanine nucleotide-binding protein in the regulation by adenosine of cardiac potassium conductance and force of contraction. Evaluation with pertussis toxin.
In atrial cardiac preparations adenosine exerts a receptor-mediated negative inotropic effect due to an increased potassium conductance. Pretreatment of guinea pigs with pertussis toxin abolished the negative inotropic and action potential shortening effect of adenosine and the adenosine analogue (-)-N6-phenylisopropyladenosine (PIA). As pertussis toxin specifically inactivates guanine nucleotide-binding proteins involved in the signal transfer from receptor binding to specific cell functions, it is concluded that a guanine nucleotide-binding protein is involved in the regulation of the receptor-mediated change in potassium conductance and force of contraction.
D000200:Action Potentials / Q000187:drug effects; D000241:Adenosine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D019204:GTP-Binding Proteins / Q000502:physiology*; D006168:Guinea Pigs; D006325:Heart Atria; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects*; D037342:Pertussis Toxin; D010660:Phenylisopropyladenosine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011188:Potassium / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D010566:Virulence Factors, Bordetella; D010660:Phenylisopropyladenosine; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D000241:Adenosine; D011188:Potassium