title: Beta-adrenoceptors of the human myocardium: determination of beta 1 and beta 2 subtypes by radioligand binding.
abstract: beta-Adrenoceptors of the human myocardium were investigated with binding studies using 125iodocyanopindolol (ICYP) as ligand. Inhibition of ICYP-binding by betaxolol (a selective beta 1-antagonist) and ICI 118551 (a selective beta 2-blocking drug) resulted in non-linear Scatchard-plots suggesting that both beta-adrenoceptor subtypes are present in human left atrium and left ventricle. Computer analysis of the data gave a beta 1/beta 2-adrenoceptor ratio of approximately 65:35 both for left atrium and for left ventricle.
mesh_terms: D001667:Binding, Competitive; D006325:Heart Atria / Q000378:metabolism; D006352:Heart Ventricles / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D020120:Iodocyanopindolol; D009206:Myocardium / Q000378:metabolism*; D010869:Pindolol / Q000031:analogs & derivatives; D011869:Radioligand Assay; D011943:Receptors, Adrenergic, beta / Q000145:classification* / Q000187:drug effects / Q000378:metabolism
chemical_list: D007457:Iodine Radioisotopes; D011943:Receptors, Adrenergic, beta; D020120:Iodocyanopindolol; D010869:Pindolol