[The functional characteristics of the beta 2-adrenoreceptors on the isolated membranes and intact erythrocytes of rats].
The main parameters of [3H]-propranolol binding were determined for beta-adrenoreceptors of membrane preparations and intact erythrocytes of white rats. It was shown that two molecules of [3H]-propranolol bind to one beta-adrenoreceptor. Two pools of adrenoreceptors differing in their affinity to the ligand and their number on the erythrocyte membrane were identified. In experiments on ligand binding to intact erythrocytes, dissociation constants (Kd) of high-affinity and low-affinity pools differed by a factor of 17 (0.92 +/- 0.22 and 15.39 +/- 2.69 nM, respectively); the number of receptors per cell differed by a factor of 9 (28 +/- 6 and 258 +/- 58). The maximal number of adrenoreceptors per erythrocyte was 286 +/- 57. In experiments with erythrocyte membrane preparations, dissociation constants of high-affinity and low-affinity pools differed by a factor of 25 (0.74 +/- 0.04 and 18.47 +/- 0.71 nM, respectively). The number of binding sites for the ligand differed by a factor of 3 (15.88 +/- 7.53 and 71.55 +/- 43.68 fmoles/mg protein, respectively). The main parameters of the ligand-receptor interaction obtained using two methods gave similar quantitative characteristics of the functional activity of erythrocyte beta-adrenoreceptors.
Smurova
E A
EA
D000818:Animals; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D008024:Ligands; D008297:Male; D011433:Propranolol / Q000493:pharmacokinetics; D011485:Protein Binding; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D018343:Receptors, Adrenergic, beta-2 / Q000032:analysis / Q000378:metabolism*
D008024:Ligands; D018343:Receptors, Adrenergic, beta-2; D011433:Propranolol
Funktsional'naia kharakteristika beta 2-adrenoretseptorov izolirovannykh membran i intaktnykh éritrotsitov krys.