Radioligand saturation binding experiments over large concentration ranges

Receptor analysis using the radioligand binding saturation method in situat ions requiring a large concentration range of the ligand is theoretically s traightforward but in practice can be relatively difficult. In this paper w e review three approaches for carrying out such experiments and assess the strengths and weaknesses of each, The three are two saturation experiments, two homologous competition experiments, and the mixed homologous saturatio n experiment. The best approach depends upon the experimental conditions an d constraints of the system studied, but in general the mixed homologous sa turation experiment appears to be the most effective at minimizing the amou nt of radioligand needed while providing the greatest reliability in the re sults. (C) 2000 Elsevier Science Inc. All rights reserved.