title: Inhibition of isoproterenol positive atrial chronotropic effect by methylmethacrylate polymer and monomer.
abstract: Atria from rats exposed in vivo to methylmethacrylate polymer or monomer were superfused and chronotropic responses to isoproterenol determined. Control and polymer-exposed atria superfused with oxygen-saturated buffer yielded dose-response curves which were essentially identical with regard to maximal increase and potency of isoproterenol. Control atria superfused with buffer containing 70% of possible oxygen saturation showed a 10-fold decrease in isoproterenol potency and a maximal effect approximately 75-80% that of fully oxygenated atria. Atria exposed to methylmethacrylate polymer and superfused with 70% oxygen saturated buffer showed a 100-fold decrease in isoproterenol potency and a maximal effect approximately 25% that of fully oxygenated control atria. Exposure of rats to methylmethacrylate monomer in vivo resulted in complete abolition of the chronotropic response to isoproterenol in atria superfused with 70% oxygen saturated media.
mesh_terms: D000818:Animals; D016275:Atrial Function; D006325:Heart Atria / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects*; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D020366:Methylmethacrylate; D008768:Methylmethacrylates / Q000494:pharmacology*; D010100:Oxygen; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D008768:Methylmethacrylates; D020366:Methylmethacrylate; D007545:Isoproterenol; D010100:Oxygen