Interactions of radiolabelled ligands with specific receptors: an analysis.

The binding and displacement of beta-adrenoceptor blockers, [3H]propranolol ([3H]PRP) and [3H]dihydroalprenolol ([3H]DHA), were studied on isolated rat erythrocytes, their membranes and ghosts; the binding of [3H]DHA and a M-cholinoceptor blocker, [3H]quinuclidinylbenzylate ([3H]QNB), on cerebral cortex membranes. In all experiments, ligand-receptor interactions conformed to a model of two pools of receptors in the same effector system and the binding of two ligand molecules to the receptor. The results were similar for the displacement of [3H]PRP, [3H]DHA and [3H]QNB with propranolol, dihydroalprenolol and quinuclidinyl-benzylate, respectively.

An approach to analysis of radiolabeled ligand interactions with specific receptors.

The aim of the study was to reveal general characteristics of the ligand-receptor interaction in the binding and displacement of radiolabeled ligands. The binding and displacement of DL-[3H]propranolol hydrochloride ([3H]propranolol) and L-[propyl-2,3, -3H]dihydroalprenolol ([3H]dihydroalprenolol), beta-adrenoceptor antagonists, were studied with isolated rat red blood cells, their membranes and ghosts. The binding of [3H]dihydroalprenolol and L-quinuclidinyl-[phenyl-4-3H]-benzylate ([3H]quinuclidinyl benzylate), a muscarinic acetylcholine receptor antagonist, was studied with cerebral cortex membranes.

The effect of heat shock on M-cholinoreceptors from rat cerebral cortex membranes.

The major parameters of binding the specific blocker [3H]quinuclidinyl benzylate were obtained for M-cholinoreceptors of rat cerebral cortex membranes. One receptor was shown to bind two molecules of the ligand; two discrete receptor pools were revealed, which differed in the sensitivity (Kd1 = 0.35 +/- 0.