title: Apparent equilibrium constant between beta-adrenoceptors and a competitive antagonist on a cultured pacemaker cell of mammalian heart.
abstract: Heart cells from newborn rats and kittens were cultured.  In both species the rate of pacemaker activity of single, cultured cells was increased by low concentrations of catecholamines.  Tthe beta-adrenoceptor blocker (minus)-KL255 antagonized competitively the effects of both, (minus)-noradrenaline and (minus)-isoprenaline.  A mean equilibrium constant of 3.6 times 10-10M between (minus)-KL255 and beta-adrenoceptors of single cells was estimated.
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D001667:Binding, Competitive; D002082:Butylamines / Q000494:pharmacology; D002415:Cats; D002478:Cells, Cultured; D007545:Isoproterenol / Q000037:antagonists & inhibitors; D007700:Kinetics; D008858:Microscopy, Phase-Contrast; D009206:Myocardium / Q000166:cytology; D009638:Norepinephrine / Q000037:antagonists & inhibitors; D010647:Phenyl Ethers / Q000494:pharmacology; D011412:Propanolamines / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D011941:Receptors, Adrenergic; D012849:Sinoatrial Node / Q000166:cytology / Q000187:drug effects*
chemical_list: D000319:Adrenergic beta-Antagonists; D002082:Butylamines; D010647:Phenyl Ethers; D011412:Propanolamines; D011941:Receptors, Adrenergic; D007545:Isoproterenol; D009638:Norepinephrine