Functional evidence against the existence of beta 2-adrenoceptors mediating positive intropic effects in guinea-pig right ventricular myocardium.
In guinea-pig isolated papillary muscles we studied the positive inotropic effects of the beta-adrenoceptor agonists isoprenaline, fenoterol and noradrenaline in the presence and absence of the beta 1-selective antagonist atenolol and the beta 2-adrenoceptor antagonist ICI 118.551. In Schild regression analysis pA2 values, for either atenolol (7.14-7.16) and ICI 118.551 (6.79-6.84) were independent of the agonists used. These results support the view that the inotropic response in guinea-pig ventricular myocardium is mediated by beta 1-adrenoceptors only.
Mügge
A
A
Division of Cardiology, Hannover Medical School, Germany.
Oldenburg
J
J
Schmitz
W
W
Scholz
H
H
D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects*; D010210:Papillary Muscles / Q000187:drug effects / Q000502:physiology; D011412:Propanolamines / Q000494:pharmacology; D018343:Receptors, Adrenergic, beta-2 / Q000502:physiology*
D011412:Propanolamines; D018343:Receptors, Adrenergic, beta-2; C026777:ICI 118551; D001262:Atenolol