Publisher Summary This chapter illustrates selected pharmacological methods, such as binding experiments and functional assays. The aim of binding experiments is to measure the binding of a radioligand (or ligand that is traceable by other means) to a receptor. The objective is to obtain an estimate of the equilibrium dissociation constant of the radioligand-receptor complex and also the maximal number of binding sites. In this process, the receptor preparation is incubated with a range of concentrations of radioligand and again in the presence of a high concentration of nonradioactive receptor-selective ligand to give a measure of nonspecific binding (nsb). After a period of equilibration (30 to 90 min), the amount of bound ligand is quantified and the total binding and nsb are fit to simultaneous equations to yield a measure of the ligand specifically bound to a receptor. In functional assays the aim is mathematical estimation of concentrations on a dose-response curve that produces the same magnitude of response as those on another dose-response curve. This is a procedure common to many pharmacological methods aimed at estimating dose-response curve parameters. In this process a function is fit to both sets of data points and a set of responses is chosen that has data points for at least one of the curves that is within the range of the other curve. A metameter of the fitting function is then used to calculate the concentrations of agonist for the other curve that produces the designated responses from the first curve.
