Radioligands ligand-receptor interactions

The design of assay systems is another particularly important factor for testing the sample compounds. Assays have to be specific and sensitive. The assays used for HTS come in many forms. There are binding assays, or enzyme-based or cell-based assays. Cell-based assays have become an important test compared with other in vitro assays, as they can provide information about bioavailability, cytotoxicity and effects on biochemical pathway. Invariably, the enzyme-based and cell-based assay systems consist of receptors or mimetics of receptors (components that mimic active parts of receptors). Normally the assays are linked to an indicator that shows the ligand-receptor interaction as some forms of signal. Radioligand binding... 

Assuming that all interactions of the species are possible, the system consists of the receptor CCR5 [R], radioligand CD4 [CD]), viral coat protein gpl20 [gp], and potential displacing ligand [B] ... 

Both the onset of binding, when the radioligand is first applied, and offset, when dissociation is promoted, can be studied directly. The relevant kinetic equations relating to the simple bimolecular interaction of ligand with receptor are presented in Chapter 1, Section 1.3. 

Wang, J.-X., Yamamura, H. I., Wang, W, Roeske, W. R. The use of the filtration technique in in vitro radioligand binding assays for membrane-bound and solubilized receptors, in Receptor-Ligand Interactions. A Practical Approach, ed. Hulme, E. C., IRL Press, Oxford,... 

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